So the distance between X and Z is simply 80 km. Rounded to one decimal place, this is 80.0 km.
What is trigonometry?Trigonometry is a branch of mathematics that focuses on the relationships between the sides and angles of triangles. It involves the study of trigonometric functions, which relate angles and sides of a right triangle, as well as the application of these functions to various real-world problems such as navigation, physics, and engineering. Trigonometry has a wide range of applications in fields such as science, engineering, architecture, and more.
Here,
First, we need to find the coordinates of each point. Let's assume that X is located at the origin (0,0) on the map. From X, we know that Y is 80 km away on a bearing of 190°. This means that Y is located 80 km to the southwest of X. To find the coordinates of Y, we need to use trigonometry. Let's define angle A as the angle between the positive x-axis and the line XY. Then we can use the cosine and sine functions to find the x and y coordinates of Y:
cos(A) = adjacent/hypotenuse = x/80
sin(A) = opposite/hypotenuse = -y/80 (note the negative sign because Y is southwest of X)
Solving for x and y, we get:
x = 80 cos(A)
y = -80 sin(A)
Now we need to find the coordinates of Z. We know that Z is due south of X, which means it lies on the y-axis. We also know that Z is on a bearing of 140° from Y, which means it forms a 40° angle with the negative y-axis. Let's call this angle B. Using trigonometry again, we can find the distance between Y and Z (which we'll call d) and the coordinates of Z:
cos(B) = adjacent/hypotenuse = x/d
sin(B) = opposite/hypotenuse
= -y/d (again note the negative sign)
We want to find d, so we can rearrange the cosine equation:
d = x/cos(B)
Substituting in the expressions for x and y in terms of A, we get:
d = (80 cos(A))/cos(B)
Finally, we need to eliminate the variables A and B. We know that A + B = 180° because angle AYX + angle BYZ = 180°. Rearranging, we get:
B = 180° - A
Substituting into the expression for d, we get:
d = (80 cos(A))/cos(180°-A)
Simplifying using the cosine difference identity, we get:
d = (80 cos(A))/(-cos(A))
= -80
This negative distance means that Z is actually due north of X, which makes sense because it is "directly south" of X on the map. So the distance between X and Z is simply 80 km.
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please help, i do not understand. thank you!
Answer: it's 1
Step-by-step explanation:
The x in the numerator determines that the x is in absolute value, meaning only positive integers.
That wouldn't matter anyway, because since any value of x would have to be greater than 0 (meaning only positive values), and both x's are the same x, the equation would have to equal one.
For example, you could plug in 2 to both x's. 2/2 is 1.
Or you could plug in 289 to both x's, in which 289/289 is 1.
No matter what number, as long as it's positive, will be 1.
If A=1+r+7r^2 and B=1-r^2, find an expression that equals A+3B in standard form.
Answer:
To find A+3B, we need to first find A and B. A = 1 + r + 7r^2 B = 1 - r^2 Now we can substitute these expressions into A+3B: A+3B = (1 + r + 7r^2) + 3(1 - r^2) Simplifying this expression, we get: A+3B = 1 + r + 7r^2 + 3 - 3r^2 A+3B = 4 + r + 4r^2 So the expression that equals A+3B in standard form is 4 + r + 4r^2.
Can anyone please answer this question
The area of shaded part in the figures are
1. 7.07cm²
2. 19.54cm²
What's area of a shape?The area is the amount of space within the perimeter of a 2D shape. It is measured in square units, such as cm², m², etc.
The area of a sector is expressed as:
A= tetha/360 × πr²
Area of the shaded part = area of big sector - area of small sector.
1. area of big sector = 90/360 × 3.14 × 5²
= 7065/360
= 19.63cm²
area of small sector = 90/360 × 3.14 × 4²
= 12.56cm²
area of shaded part = 19.63 - 12.56
= 7.07cm²
2. Area of big sector = 40/360 × 3.14 × 9²
= 28.26cm²
area of small sector = 40/360 × 3.14 × 5²
= 8.72
area of shaded part = 28.26-8.72
= 19.54cm²
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which statement about a quadrilateral is true? responses a rhombus has exactly one pair of parallel sides. a rhombus has exactly one pair of parallel sides. a trapezoid has two pairs of parallel sides. a trapezoid has two pairs of parallel sides. all rectangles are squares. all rectangles are squares. some rhombuses have four right angles.
The statement that is true about rhombus is d. some rhombuses have four right angles.
A rhombus is a parallelogram with equal-length sides, though the angles at the opposing ends need not be equal, nor must the sides be parallel. If a rhombus is also a cube, it can have four right angles. It can be viewed as an equal-sided trapezoid as well.
A parallelogram has two sets of parallel sides, whereas a trapezoid only has one pair of parallel sides. Therefore, it is untrue that a trapezoid has two sets of parallel edges. Not all rectangles are squares, but they are all quadrilaterals with four right angles. A unique variety of parallelogram called a square has equal-length edges. Therefore, it is untrue to say that all circles are squares.
Complete Question:
which statement about a quadrilateral is true?
a. a rhombus has exactly one pair of parallel sides.
b. a trapezoid has two pairs of parallel sides.
c. all rectangles are squares.
d. some rhombuses have four right angles.
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What is the range of the function f(x) = -3x - 4 when the domain is {-1, 0, 1}
Step-by-step explanation:
For: x=-1
f(x)= -3*-1 -4 =-1
For: x=0
f(x)= -3*0-4 =-4
For: x=1
f(x)= -3*1 -4 =-7
Therefore, the range of f(x)= [-1, -4, -7]
Complete the proof that the alternate interior angles of transversals of
parallel lines are congruent.
Note: this proof is for the case where m/1 is less than 90°.
This proof uses the following theorem: Any point on one parallel line is the
same distance from the other line on a perpendicular transversal.
Statement or construction
1 ABCĎ
2 Construct BE perpendicular to such
that point E is on CD
3 Construct CF perpendicular to AB such
that point F is on AB
4 m/CFB=m/BEC = 90°
5 CF=
6
BC= BC
7 ABCF ACBE
8 LFBC ZECB
Reason
Given
All perpendicular angles measure 90° (2.
3).
Any point on one parallel line is the same
distance from the other line on a
perpendicular transversal (1, 2, 3).
They are measures of the same segment.
congruence (4, 6,5)
Corresponding parts of congruent figures
are congruent (7)
The two column proof is completed as follows
Statement Reason
1. AB || CD Given
2 Construct BE perpendicular to Construction of side BE
CD such that point E is on CD
3 Construct CF perpendicular to Construction of side CF
AB such that point F is on AB
4 ∠ CFB = ∠ BEC = 90° All perpendicular angles measure 90°
5 CF = BE Any point on one parallel line is the
same distance from the other line on
a perpendicular transversal (1, 2, 3)
6. BC = BC They are measures of the same
segment.
7. Δ BCF ≅ Δ CBE SAS congruence (4, 6,5)
What is SAS congruence theoremThe SAS congruence theorem, also known as the Side-Angle-Side congruence theorem, states that if two triangles have two sides and the included angle of one triangle congruent to the corresponding parts of another triangle, then the triangles are congruent.
The equality of the included angle is by the alternate interior angles theorem.
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If a function is defined as f(x)=2x+3 , find the value of f(4
Answer: f(4) = 11
Step-by-step explanation: See image below.
Answer: 11
Step-by-step explanation:
you need to put 4 where the X is: f(4)=(2*4)+3 = 11
Please help and include scratch thank you.
Hence, the value of y is 23 when x = 7.
Describe equation?
A mathematical equation is a formula that uses the equals symbol (=) to denote the equality of two expressions.
A formula would be 3x - 5 = 16,
for instance. We may determine the value of the variable x by solving this equation: x = 73.
The slope-intercept representation of the equation can be used to determine the equation of a line running through the points (x1, y1) and (x2, y2):
y - y1 = m(x - x1) (x - x1)
where m is the line's slope. The following formula can be used to determine the line's slope:
m = (y2 - y1) / (x2 - x1) (x2 - x1)
Now put the x and y value in this:
slope of the line using the points (1, 5) and (3, 11):
m = (11 - 5) / (3 - 1) = 6 / 2 = 3
We can use the slope of the line to determine the equation of the line now that we know it:
y - y1 = m(x - x1) (x - x1)
y - 5 = 3(x - 1) (x - 1)
y - 5 = 3x - 3 = 3x + 2
In light of this, the equation for the line connecting points (1, 5) and (3, 11) is y=3x+2
To determine the value of y for x = 7, we can utilize the equation of the line we discovered earlier:
y = 3x + 2
y = 3(7) + 2
y = 21 + 2
y = **23**
Graph calculation given below:
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a programmer plans to develop a new software system. in planning the operating system, he needs the estimate the % of computers that use a new operating system. how many computers must be surveyed in order to be 95% within 4% margin of erro
To be 95% confident within a 4% margin of error, the programmer must survey at least 601 computers.
To estimate the percentage of computers that use a new operating system with a 95% confidence level and a 4% margin of error, you must first determine the required sample size. Here's a step-by-step explanation:
Identify the confidence level and margin of error: In this case, the confidence level is 95% and the margin of error is 4%.
Determine the standard value (Z-score) for the desired confidence level: For a 95% confidence level, the Z-score is 1.96. This value can be found using a Z-score table or an online calculator.
Use the formula for sample size calculation:
n = (Z^2 * p * (1-p)) / E^2
Where n is the required sample size, Z is the Z-score, p is the estimated proportion of computers using the new operating system, and E is the margin of error.
Since we do not have an estimate for the proportion (p), we will assume the worst-case scenario (p=0.5) to ensure the largest possible sample size:
n = (1.96^2 * 0.5 * 0.5) / 0.04^2
Calculate the sample size:
n ≈ (3.8416 * 0.25) / 0.0016
n ≈ 0.9604 / 0.0016
n ≈ 600.25
Round up to the nearest whole number: Since we cannot survey a fraction of a computer, we will round up to the next whole number, which is 601.
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a survey asks teachers and students whether they would like the new school mascot to be a viking or a patriot. this table shows the results. which statement is true
Answer:
Option D.
Step-by-step explanation:
According to this survey results:
Students: 80 like viking and 20 like patriot.
Teachers: 5 like viking and 15 like patriot.
In Option A it is given that patriot is more popular in students while viking is more popular in teachers which is not correct.
In option C patriot is equally popular in students and teachers, which is also not correct. because patriot is popular in 20% of students but 80% in teachers, which is not correct.
In option B there is no difference between students and teachers, this statement is also not correct because there is lots of differences in their choices.
In Option D it is said that viking is more popular in students but patriot is more popular in teachers. this is correct.
A rectangular prism has a base area of 54 m (to the 2nd power) and a volume of 702 m (to the 3rd power). What is its height?
Answer:
13 meters.
Step-by-step explanation:
We can use the formula for the volume of a rectangular prism, which is:
Volume = length x width x height
We are given that the base area (length x width) of the prism is 54 m², so we can write:
length x width = 54 m²
We are also given that the volume of the prism is 702 m³, so we can write:
Volume = length x width x height = 702 m³
We want to find the height of the prism, so we can rearrange the formula for the volume to solve for height:
height = Volume / (length x width)
Substituting the given values, we get:
height = 702 m³ / 54 m²
Simplifying this expression, we can divide both the numerator and the denominator by the greatest common factor of 54 and 702, which is 18:
height = (702/18) m / (54/18) m = 39 m / 3 m
height = 13 meters
Therefore, the height of the rectangular prism is 13 meters.
10. A piece of cardboard is 12 x 15 inches. What is the max volume of an open-roof box that can be formed by folding up the sides to create a height of x? ROUND ANSWER TO THE NEAREST WHOLE NUMBER
Answer:
180 fr
Step-by-step explanation:
its too hard
An experiment consists of drawing a card and recording its color, then rolling a die and recording its value.
Is the following tree diagram correct based on the describes situation AND explain how you know.
thx
The probabilities of rolling each number on the die are 1÷6, which is correctly represented by the branching probabilities from each die-rolling node.
What is an experiment ?
In science and statistics, an experiment is a controlled procedure designed to test a hypothesis or to investigate the effect of one or more factors or variables on an outcome of interest. The experiment involves manipulating one or more variables and observing the effect on one or more outcomes while controlling other factors that might influence the outcome(s).
Based on the image provided, the tree diagram appears to be correct for the described situation. The first event is drawing a card, which has two possible outcomes: "red" and "black." From each outcome of drawing a card, there are six possible outcomes of rolling a die: 1, 2, 3, 4, 5, and 6. The diagram correctly shows all of these possible outcomes and the probabilities of each outcome, assuming that the deck of cards is a standard deck with 26 red cards and 26 black cards, and the die is fair. The branching probabilities from the "drawing a red card" node are 26÷52 or 0.5, and the branching probabilities from the "drawing a black card" node are also 26÷52 or 0.5.
Therefore, The probabilities of rolling each number on the die are 1/6, which is correctly represented by the branching probabilities from each die-rolling node.
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I need help with these questions
PLEASE HELP ME PLEASE SHOW EXPLANATION WHEN SOLVING IT OR I WILL REPORT YOUUU
Answer:
[tex]x {}^{2} - 5[/tex]
Mr James works a basic week of 40 hours at a rate of $16 an hour. His overtime rate
is $4 per hour MORE than his basic rate.
Calculate:
(a) his total wage for a basic week,
(b) his wage for a week in which he worked 47 hours,
(c) the number of hours he worked during one week if he was paid a wage of $860.
Answer:
Sure, I can help you with that. (a) His total wage for a basic week can be calculated as follows: Total wage for a basic week = Basic rate per hour x Number of hours worked in a basic week Total wage for a basic week = $16 x 40 Total wage for a basic week = $640 Therefore, his total wage for a basic week is $640. (b) His wage for a week in which he worked 47 hours can be calculated as follows: Wage for a week with overtime = (Basic rate per hour + Overtime rate per hour) x Number of overtime hours worked + Total wage for a basic week Overtime rate per hour = Basic rate per hour + $4 Overtime rate per hour = $16 + $4 Overtime rate per hour = $20 Wage for a week with overtime =$16
consider the following data for two independent random samples taken from two normal populations. sample 1 sample 2 10 7 13 7 9 8 8 4 6 9 8 7 a. compute the two sample means. b. compute the two sample standard deviations. c. what is the point estimate of the difference between the two population means? d. what is the 90% confidence interval estimate of the difference between the two population means?
a. The sample mean for sample 1 is 9.2, and the sample mean for sample 2 is 7.17.
b. The sample standard deviation for sample 1 is approximately 3.29, and the sample standard deviation for sample 2 is approximately 3.65.
c. The point estimate of the difference between the two population means is 2.03.
d. The 90% confidence interval estimate of the difference between the two population means is [-0.44, 4.50].
a. The sample mean for sample 1 is
(10 + 13 + 9 + 8 + 6) / 5 = 9.2
The sample mean for sample 2 is
(7 + 7 + 8 + 4 + 9 + 8) / 6 = 7.1667 ≈ 7.17
b. The sample standard deviation for sample 1 is:
√[((10-9.2)² + (13-9.2)² + (9-9.2)² + (8-9.2)² + (6-9.2)²) / (5-1)]
= √[10.8] ≈ 3.29
The sample standard deviation for sample 2 is
√[((7-7.17)² + (7-7.17)² + (8-7.17)² + (4-7.17)² + (9-7.17)² + (8-7.17)²) / (6-1)]
= √[13.33] ≈ 3.65
c. The point estimate of the difference between the two population means is:
9.2 - 7.17 = 2.03
d. To calculate the 90% confidence interval estimate of the difference between the two population means, we need to first calculate the standard error of the difference between the sample means:
s.e.(difference between sample means) = √[(s1²/n1) + (s2²/n2)]
= √[(3.29²/5) + (3.65²/6)]
= √[2.60]
≈ 1.61
Next, we can use the t-distribution with degrees of freedom equal to the smaller of n1-1 and n2-1 (in this case, 4) and a 90% confidence level to find the critical value, t*:
t* = 1.533 (from t-distribution table or calculator)
Finally, we can construct the confidence interval estimate:
9.2 - 7.17 ± (t* * s.e.(difference between sample means))
= 2.03 ± (1.533 * 1.61)
= 2.03 ± 2.47
= [ -0.44 , 4.50 ]
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An investor has an account with stock from two different companies. Last year, her stock in Company A was worth $5800 and her stock in Company B was worth $7470. The stock in Company A has decreased 1% since last year and the stock in Company B has decreased 20%. What was the total percentage decrease in the investor's stock account? Round your answer to the nearest tenth (if necessary).
To find the total percentage decrease, we first need to find the new values of the stocks in Company A and Company B after the decrease.
The new value of the stock in Company A is: $5800 - (1% \times $5800) = $5742
The new value of the stock in Company B is: $7470 - (20% \times $7470) = $5976
To find the total value after the decrease, we add these two values: $5742 + $5976 = $11718
To find the percentage decrease from the original total value ($5800 + $7470 = $13270) to the new total value ($11718), we use the formula:
percentage decrease = [(original value - new value) / original value] x 100%
percentage decrease = [($13270 - $11718) / $13270] x 100%
percentage decrease = 11.7%
Therefore, the total percentage decrease in the investor's stock account is 11.7%.
Find the circumference of great circle of sphere whose volume is 36πcm^3
Answer:
The formula for the volume of a sphere is:
V = (4/3)πr^3
where V is the volume and r is the radius of the sphere.
We are given that the volume of the sphere is 36π cm^3, so we can write:
36π = (4/3)πr^3
Simplifying:
r^3 = (36/4) * 3
r^3 = 27
r = 3
Therefore, the radius of the sphere is 3 cm.
The circumference of a great circle on a sphere is given by the formula:
C = 2πr
where r is the radius of the sphere.
So, the circumference of the great circle is:
C = 2π(3) = 6π
Therefore, the circumference of the great circle of the sphere is 6π cm.
Work out and simplify 3/8 - 1/16
Answer:
3/8 - 1/16 simplifies to 5/16.
Step-by-step explanation:
To subtract two fractions, we need to find a common denominator. In this case, the least common multiple of 8 and 16 is 16.
So, we need to rewrite 3/8 and 1/16 with a denominator of 16:
3/8 = 6/16
1/16 = 1/16
Now we can subtract:
6/16 - 1/16 = 5/16
AnswerAns
5/6
Step-by-step explanation
3/8 - 1/16 = (3×2 -1)÷16 = 5/16
Write f(x) = 5(x - 2)2 - 7 in standard form.
To write f(x) = 5(x - 2)2 - 7 in standard form, we need to expand the squared term first:
f(x) = 5(x - 2)(x - 2) - 7
f(x) = 5(x2 - 4x + 4) - 7
f(x) = 5x2 - 20x + 13
Therefore, the standard form of f(x) = 5(x - 2)2 - 7 is f(x) = 5x2 - 20x + 13.
Answer: f(x)=5x2−20x+13
Step-by-step explanation:
DUE TODAY PLEASE HELP!!!!
For which angles is the cosine positive? Select all that apply.
a
0 radians
b
5π/12 radians
c
5π/6 radians
d
3π/4 radians
e
5π/3 radians
Step-by-step explanation:
if it is between 0 and pi/2 (90°), or between 3pi/2 (270°) and 2pi (360°).
for angle = 0, cos = 1. therefore, positive.
0 <= 5pi/12 <= pi/2. therefore, positive.
pi/2 <= 5pi/6 <= pi. therefore, negative.
pi/2 <= 3pi/4 <= pi. therefore, negative.
3pi/2 <= 5pi/3 <= 2pi. therefore, positive.
you do know how to compare fractions, right ?
you need to bring then to the same denominator by multiplying numerator and denominator by the same factor.
e.g. comparing 5pi/12 with pi/2.
to bring them both to .../12, we have to multiply pi/2 by 6/6.
so, we are comparing 5pi/12 and 6pi/12.
and we see, 5pi/12 is smaller.
the others work the same way.
3pi/6 <= 5pi/6 <= 6pi/6
2pi/4 <= 3pi/4 <= 4pi/4
9pi/6 <= 10pi/6 <= 12pi/6
now you see it clearly.
PR is tangent to circle Q at Point R. PS is tangent to circle Q at Point S. Find m
Answer:
142
Step-by-step explanation:
∠P + ∠Q = 180
38 + ∠Q = 180
Subtract 38 from both sides
∠Q = 142 degrees
suppose 40% of the people at a large meeting are republican. a sample of 20 is randomly selected to take part in a certain activity. to determine the probability that less than 45% of the sample is republican, what would be the standard deviation used in the z-score calculation?
What is the minimum value of the function over the interval -5 < x < 5? h(x) = log[(x – 5)2 + 3]
The minimum value of the function h(x) = log[(x - 5)² + 3] over the interval -5 < x < 5 is approximately log[3.000001].
The minimum value of the function h(x) = log[(x - 5)² + 3] over the interval -5 < x < 5 can be found through the following.
Recognize that the logarithm function is increasing.
Minimize the argument of the logarithm, i.e., (x - 5)² + 3.
Observe that (x - 5)² is always non-negative since it is a square of a real number.
The minimum value of (x - 5)² occurs when x = 5 (in this case, (x - 5)² = 0).
However, x cannot be equal to 5 because the interval is -5 < x < 5.
Since the interval is open, find the minimum value for (x - 5)² in this interval, which occurs when x is as close to 5 as possible within the given interval. This would be x = 4.999.
Substitute this value of x into the function:
h(x) = log[(4.999 - 5)² + 3] = log[0.001² + 3] ≈ log[3.000001].
Hence, the minimum value of the function h(x) = log[(x - 5)² + 3] over the interval -5 < x < 5 is approximately log[3.000001].
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I'm stressing really bad because I don't know how to solve this math time series question. IF SOMEONE COULD PLEASE LEND ME THEIR EXPERTISE AND GENIUSNESS, I HOPE YOU ARE UNCEASINGLY BLESSED!
The predicted sales for week 10 is 30.143.
What is median?Median is a measure οf central tendency that represents the middle value in a dataset when the values are arranged in οrder οf magnitude.
Tο remοve the aberrant values frοm the time series data, we can replace them with dummy values. We can use the mean οr median οf the remaining values in the series tο replace the aberrant values.
Using mean as the replacement value, we get:
Week 1 2 3 4 5 6 7
Sales 26 28 27 30 23 23 38
Now we can use a regression model to predict the sales for week 10. Let's assume a linear regression model:
Sales = a + b*Week
where a is the intercept and b is the slope of the regression line.
To fit the model, we can use the sales data for weeks 1-7:
Week 1 2 3 4 5 6 7
Sales 26 28 27 30 23 23 38
The least squares estimates for the model parameters are:
b = 1.6429
a = 14.7143
Using these parameter estimates, we can predict the sales for week 10:
Sales(10) = a + b10
= 14.7143 + 1.642910
= 30.143
Therefore, the predicted sales for week 10 is 30.143.
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a river starts by flowing south about 1.1x10 to the seventh power then it flows southeast for about 3.2x10 to the sixth power ft before it empties into the ocean. what is the length of the river? write your answer using scientific notation show your work
1.143 x 10⁷ ft, or approximately 11.43 million feet is the length of the river.
To find the length of the river, we need to use the Pythagorean theorem, which states that the square of the length of the hypotenuse (the diagonal line connecting the two endpoints of a right triangle) is equal to the sum of the squares of the lengths of the other two sides.
Let's call the length of the southward flowing part of the river "a" and the length of the southeastward flowing part of the river "b". Then we have:
a = 1.1 x 10⁷ ft
b = 3.2 x 10⁶ ft
The length of the river is given by the hypotenuse of a right triangle with sides a and b. Therefore, we can calculate the length of the river, c, as follows:
c² = a² + b²
c² = (1.1 x 10⁷ ft)² + (3.2 x 10⁶ ft)²
c² = 1.21 x 10¹⁴ ft² + 1.024 x 10¹³ ft²
c² = 1.3104 x 10¹⁴ ft²
c = √(1.3104 x 10¹⁴ ft²)
c = 1.143 x 10⁷ ft
Therefore, the length of the river is 1.143 x 10⁷ ft, or approximately 11.43 million feet
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Ryan Is in charge of planning a reception for 2600 people. He is trying to decide which snacks to buy. He has asked a random sample of people who are coming to the reception what their favorite snack is. Here are the results.
we get a predicted number of 1111 people whose favorite snack will be pretzels or cookies at the reception.
How to deal with random sample?
The sample provides information about the favorite snack of a random sample of people, but we need to use this information to make a prediction about the whole population of 2600 people.
First, we can calculate the proportion of the sample who chose pretzels or cookies as their favorite snack:
proportion = (number of people who chose pretzels + number of people who chose cookies) / total number of people in the sample
proportion = (16 + 54) / (30 + 16 + 54 + 64)
proportion = 70 / 164
proportion ≈ 0.4268
Next, we can use this proportion to estimate the number of people who will choose pretzels or cookies as their favorite snack out of the whole population:
predicted number of people = proportion × total number of people in the population
predicted number of people = 0.4268 × 2600
predicted number of people ≈ 1110.8
Rounding to the nearest whole number, we get a predicted number of 1111 people whose favorite snack will be pretzels or cookies at the reception.
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Consider a circle whose equation is x2 + y2 – 2x – 8 = 0. Which statements are true? Select three options. The radius of the circle is 3 units. The center of the circle lies on the x-axis. The center of the circle lies on the y-axis. The standard form of the equation is (x – 1)² + y² = 3. The radius of this circle is the same as the radius of the circle whose equation is x² + y² = 9.
Answer:
Correct options are A, B, E--------------------------
Standard form for the equation of a circle is:
(x − h)² + (y − k)² = r², where (h, k) is the center and r is the radiusConvert the given equation into standard form:
x² + y² - 2x - 8 = 0x² - 2x + 1 + y² - 9 = 0(x - 1)² + y² = 9(x - 1)² + y² = 3²Its center is ( 1, 0) and radius is r = 3.
Let's verify the statements:
A) The radius of the circle is 3 units - TRUE, r = 3;B) The center of the circle lies on the x-axis - TRUE, point (1, 0) is on the x-axis;C) The center of the circle lies on the y-axis - FALSE, the x- coordinate of the center is not zero; D) The standard form of the equation is (x – 1)² + y² = 3 - FALSE, r²= 9 but not 3;E) The radius of this circle is the same as the radius of the circle whose equation is x² + y² = 9, TRUE, its radius is r² = 9 ⇒ r = 3.Answer:
See below
Step-by-step explanation:
To find:-
Which statements are true .Answer:-
The given equation of the circle is ,
[tex]\longrightarrow x^2+y^2-2x-8 = 0 \\[/tex]
For finding the correct statements , we need to convert this equation into standard form for a circle.
The standard equation of circle is given by,
[tex]\boxed{\begin{tabular}{c}\textbf{\underline{ \red{Standard\ equation\ of \ circle }}} \\ \\ \text{ The standard equation of a circle is given by:-} \\\\ \longrightarrow \underline{\underline{ (x-h)^2+(y-k)^2 = r {}^{2}}} \\\\ \text{where} , \\\\ \bullet\text{ (h,k) is the centre of the circle.}\\\\\bullet\text{ "r" is the radius of the circle. }\\\end{tabular}}[/tex]
Now for that we need to complete the square for "x" . This can be done by ,
Rearrange the terms,
[tex]\longrightarrow x^2-2x + y^2-8 = 0 \\[/tex]
Add and subtract 1² .
[tex]\longrightarrow ( x^2 -2x +1^2 ) - 1^2 + y^2-8=0 \\[/tex]
Simplify,
[tex]\longrightarrow (x^2-2(1)x+1^2) - 1-8 + y^2=0 \\[/tex]
Notice that the terms inside the small brackets are in the form of a² - 2ab + b² , which is the whole square of (a-b) . So we can write it as,
[tex]\longrightarrow (x-1)^2 +y^2 - 9 = 0 \\[/tex]
Add 9 on both the sides ,
[tex]\longrightarrow (x-1)^2 + y^2 = 9\\[/tex]
This can be written as,
[tex]\longrightarrow \underline{\underline{ \boldsymbol{(x-1)^2+(y-0)^2 = 3^2}}} \\[/tex]
On comparing it to the standard form, we have;
[tex]\longrightarrow\boxed{ \text{Center = (1,0) }} \\[/tex]
[tex]\longrightarrow\boxed{ \text{ Radius = 3 \ units}} \\[/tex]
Let's check the given statements ,
Statement 1: The radius of the circle is 3 units.
This statement is true as we just calculated the radius to be 3 units.Statement 2: The centre of the circle lies on the x-axis.
This statement is also true as you can see that the y coordinate to the centre is 0 , and the x coordinate is 1 , so it will be on x-axis .Statement 3: The statement of the circle lies on the y-axis.
This statement is false since in the previous statement we proved that the centre lies on the x-axis .Statement 4: The standard equation of the circle is (x-1)²+y² = 3
This statement is false as we calculated the value of r² to be 9 .Statement 5: The radius of this circle is the same as the radius of the circle whose equation is x² + y² = 9.
The given equation of circle is x² + y² = 9 , if we convert this into standard form, we will get ; x² + y² = 3² . Now on comparing it to the standard equation, we see that the radius is 3 units . Hence the given statement is also true .The graph for the same has been attached.
A scientist is studying bacterial growth over time. Her research is conducted by placing 10 strep bacteria in a petri dish containing enough food for the bacteria to live and thrive for the course of the research. She records the number of bacteria present every two hours for 6 hours. The collected data is shown in the table below and on the given graph.
a. What function, linear or exponential, do you think would be the best choice to model this data? Explain why you think your choice is the best-fit.
b. Explain how to determine which function is the best choice mathematically, without using a graph.
Demonstrate your method.
c. Think of an example of at least 4 data points that would be best modeled by the function you did NOT choose in part a. Explain how you set up the data so that it worked with this type of function.
This is reflected in the data as the number of bacteria doubles every two hours, which is a characteristic of exponential growth.
What do you mean by exponential data ?Data that changes or grows at an exponential rate over time is referred to as exponential data. This indicates that the data changes quickly, either increasing or decreasing, and that the pace of change quickens over time. Exponential data frequently consists of numbers that rise steadily over time, with the rate of rise accelerating over time.
a.) exponential function would be the ideal option to model this data. An exponential curve is produced as the quantity of bacteria multiplies at an ever-increasingly rapid rate.
b. One way to determine which function is the best choice is to examine the rate of change of the data. In this case, we may calculate the average rate of change for each time period and see if it is constant. If the rate of change is constant, the data can be represented by a linear function. However, if the rate of change increases or decreases, an exponential or quadratic function might be a better fit.
From 0 to 2 hours: (25-10)/(2-0) = 7.5
From 2 to 4 hours: (50-25)/(4-2) = 12.5
From 4 to 6 hours: (100-50)/(6-4) = 25
c. The distance travelled by an automobile at a constant pace is an illustration of data that would be best characterised by a linear function. Imagine a car driving for four hours at a speed of 60 mph. Below is a list of the distance covered each hour:
After 1 hour: 60 miles
After 2 hours: 120 miles
After 3 hours: 180 miles
After 4 hours: 240 miles
In this case, the distance traveled is directly proportional to the time, so a linear function would be the best fit.
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