the diameter of a circle is 8 cm what is its area?

Answers

Answer 1

A = πr^2 and d = 2r.

So r = 8/2 = 4 cm.

Now use the first formula

A = π(4 cm)^2 = 50.265 cm^2


Related Questions

Julie is tracking the growth of a plant for a science project. The height of the plant on the 2nd day she measured was 8 inches and on the 7th day it was 20.5 inches. Assume the relationship is linear

Answers

Answer:

Step-by-step explanation:

The relationship is linear, so the plant grows the same amount each day.

The height on the 2nd day was 8 inches:

h₂ = 8

The height on the 7th day was 20.5 inches:

h₇ = h₂ + (7-2)d = 8 + 5d = 20.5

d = 2.5

The plant grows 2.5 inches each day.

Given parallelogram RUST and m< RUT=43, what other angle has the same measurement

Answers

9514 1404 393

Answer:

  (b) ∠STU

Step-by-step explanation:

Transversal UT between parallel sides RU and ST creates alternate interior angles RUT and STU. These are congruent.

  ∠STU has the same measure as ∠RUT

_____

The figure shown is a trapezoid, not a parallelogram.

13. 30 of the 100 iPads in an inventory are known to be cracked. What
is the probability you randomly select one that is not cracked?

Answers

Answer:

7/10 or 0.7

Step-by-step explanation:

a probability is always the ratio of possible cases over all cases.

"all cases" here is 100.

possible cases are all iPads not cracked in the inventory = 70 (because 30 are cracked, that leaves 100-30=70 not cracked).

so, the probability to select a non-cracked unit is

70/100 or simplified 7/10 (or 0.7)

Use the ratio of a 45-45-90triangle to solve for the variables. Make sure to simplify radicals. Leave your answers as radicals in simplest form.

Answers

9514 1404 393

Answer:

  m = n = 5

Step-by-step explanation:

The side ratios in a 45°-45°-90° triangle are 1 : 1 : √2. That is, the hypotenuse is √2 times the side length. Here, the hypotenuse is 5√2, so the side length must be 5.

  m = n = 5

Which one is it------------------

Answers

Answer:

you're right

Step-by-step explanation:

As the number of copies increases, the dimensions of the images continue to decrease but never reach 0. Option A is correct.

As of the given statement,
Both copy machines reduce the dimensions of images that run through the machines. which statment is true is to be justified.

What is dimensions?

In mathematics, dimensions are the measurements of the size or distance of an item, region, or space in one direction. In layman's words, it is the measurement of something's length, width, and height. Length is the most commonly used dimension.

here,
Both copy machines diminish the size of images that pass through them. Which statement is correct must be justified. So, As the number of copies increases, the image dimensions drop but never reach zero.

Thus, the image dimensions decrease as the number of copies grows, but never reaches zero.

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What is the sum of the geometric sequence 1, 3, 9, ... if there are 10 terms? (5 points)

Answers

Answer:

[tex]S_n = \frac{1 (1 - 3^{10})}{1 - 3} = 29524[/tex]

Step-by-step explanation:

There's a handy formula we can use to find the sum of a geometric sequence, and here it is

[tex]S_n = \frac{a_1 (1 - r^n)}{1 - r}[/tex]

The value n represents the amount of terms you want to sum in the sequence. The variable r is known as the common ratio, and a is just some constant. Let's find those values.

First lets visualize this sequence

[tex]n_1 = 1\\n_2 = 1 + 3\\n_3 = 1 + 3 + 3^2\\n_4=1+3+3^2+3^3\\...[/tex]

Okay so there's clearly a pattern here, let's write it a bit more concisely. For each n, starting at 1, we raise 3 to the (n-1) power, add it to what we had for the previous term.

[tex]S_n = \sum{3^{n-1}} = 3^{1 - 1} + 3^{2 - 1} + 3^{3-1} ...[/tex]

Our coefficients of r, and a, are already here! As you can see below, r is just 3, and a is just 1.

[tex]S_n = \sum{a*r^{n-1}}[/tex]

To finish up lets plug these coefficients in and get our sum after 10 terms.

[tex]S_n = \frac{1 (1 - 3^{10})}{1 - 3} = 29524[/tex]

The maximum and minimum values of a quadratic function are called as________of the function.

Answers

Vertex is the point where the function is at its maximum/ minimum.

Put the following equation of a line into slope-intercept form, simplifying all fractions 2x-2y=14

Answers

Answer:

y = x - 7

Step-by-step explanation:

Answer: y = x - 7

Slope intercept form: y = mx + b

[tex]2x-2y=14\\\\-2y=-2x+14\\\\y=\frac{-2x+14}{-2} =\frac{-2(x-7)}{-2} =x-7[/tex]

Anyone knows the answer?
Please!

Answers

Answer:

C

Step-by-step explanation:

sin(theta)=7/8, theta=arcsin(7/8)=61

A certain university has 25,000 registered students. To estimate the percentage who are living at home, a simple random sample of 400 students is drawn. It turns out that 317 of them are living at home. Now, 317 out of 400 is (about) 79%. Indicate whether each quantity is actual or estimated from the data. You'll get partial credit for

Answers

Answer:

Indication of Actual Quantity and Estimated Quantity

Actual Quantity:

Registered students in the university = 25,000

Sample of students = 400

Students living at home = 317

Estimated Quantity:

317 out of 400 students

79%

Step-by-step explanation:

An actual quantity does not require to be estimated.  It is usually given in the question or scenario.  For example, the number of registered students in the university is an actual quantity.  The percentage of students who live at home from the simple random sample of 400 is an estimated quantity.

6 less than six times a number is 42 what is the number​

Answers

Answer:

x = 8

General Formulas and Concepts:

Pre-Algebra

Equality Properties

Multiplication Property of Equality Division Property of Equality Addition Property of Equality Subtraction Property of Equality

Step-by-step explanation:

Step 1: Define

Identify

6x - 6 = 42

Step 2: Solve for x

[Addition Property of Equality] Add 6 on both sides:                                    6x = 48[Division Property of Equality] Divide 6 on both sides:                                  x = 8

Answer: -6

Step-by-step explanation:

We can create an equation based on the info given.

6-6x=42 Now you solve for x, the unknown number.

-6      -6      Subtract 6 on both sides

-6x=36

/-6   /-6       Divide by -6 on both sides

x=-6

The number is -6.

Solve |6k + 12| + 9 = 9 for k.

Answers

Step-by-step explanation:

6k + 12 + 9=9

6k + 12 = 9 - 9

6k + 12 = 0

12 = -6k

12/-6 = -6k/-6

2/-1 = k

k = -2

Answer:

k=-2

Step-by-step explanation:

6k+12+9=9

subtract 9 from both sides

6k+12=0

subtract 12 from not sides

6k= -12

divide both sides by 6 (isolating the variable)

k= -12/6

simplify

k= -2

An expression is shown below:

10n3 − 15n2 + 20xn2 − 30xn

Part A: Rewrite the expression so the GCF is factored completely. (4 points)

Part B: Rewrite the expression completely factored. Show the steps of your work.

Answers

Answer:

An expression is shown below:

10n³− 15n² + 20xn² − 30xn

Part A: Rewrite the expression so the GCF is factored completely. (4 points)

10n³− 15n² + 20xn² − 30xn

2*5*n*n*n-5*3*n*n+2*5*2*x*n*n-2*5*3*x*n

Greatest common factor=5*n=5n

Part B: Rewrite the expression completely factored. Show the steps of your work.

Solution given;

10n³− 15n² + 20xn² − 30xn

5n(2n²-3n+4xn-6x)

5n(2n²+4xn-3n-6x)

5n(2n(n+2x)-3(n+2x))

5n(n+2x)(2n-3)

Answer:

[tex]5n(2n-3)(n+2x)[/tex]

Step-by-step explanation:

Step 1:   Rewrite the expression so the GCF is factored completely

[tex]10n^{3} - 15n^{2} + 20xn^{2} - 30xn[/tex]

The GCF is 5n so factor it out

[tex]5n(2n^{2} - 3n + 4xn - 6x)[/tex]

Step 2:  Rewrite the expression completely factored

[tex]5n(2n^{2} - 3n + 4xn - 6x)[/tex]

[tex]5n(2n(n+2x)-3(n+2x))[/tex]

[tex]5n(2n-3)(n+2x)[/tex]

Answer:  [tex]5n(2n-3)(n+2x)[/tex]

The circle graph above shows the distribution of utility expenses for the Hierra family last year. If the family’s total utility expenses last year were $3,600, what were their expensive go water and sewer.
Water and sewer=X%
Electric=30%
Heating and gas=50%

Answers

Answer:

The correct answer is - $720 or 20%.

Step-by-step explanation:

Given:

Total expense = 3600

Electric=30%

Heating and gas=50%

Water and sewer=X%

Solution:

For electric: 3600*30/100 = 1080

for heating and gas: 3600*50/100 = 1800

Left money for expense of water and shower = total - (electric and heating)

= 3600-1880

= 720

Percentage of water and shower = 720*100/3600

= 20%

Answer:

Correct!

Step-by-step explanation:

Thank you this is correct :) I took the test

A ball is thrown from an initial height of 4 feet with an initial upward velocity of 40 feet per second. The ball's height h (in feet) after t seconds is given by the following. h=4+40t-16t2 Find all values of for which the ball's height is 26 feet.

Answers

Answer:

Step-by-step explanation:

To find the times that the height is 26 feet, we set the position equation equal to 26 and solve for t:

[tex]26=-16t^2+40t+4[/tex] and

[tex]0=-16t^2+40t-22[/tex] and factor that however you are factoring in class to solve a problem like this. When you do that you get

t = .86 seconds and t = 1.68 seconds. That means that .86 seconds after the ball is thrown into the air, it reaches a height of 26 feet; it goes up to its max height and then gravity takes over and pulls it back down. When this happens, it will pass 26 feet again on its way back down. This second time is after 1.68 seconds.

The length of a rectangle is 10 yd less than three times the width, and the area of the rectangle is 77 yd^2. Find the dimensions of the rectangle.

Answers

Answer:

width = 7, length = 11

Step-by-step explanation:

area = 77

length = 3w - 10

width = w

w(3w - 10) = 77

3w^2 - 10w - 77 = 0

(3w + 11)(w - 7) = 0

we rule out 3w + 11 = 0 because w would be negative

so we use w - 7 = 0

so the width = 7

length = 3w - 10

length = 21 - 10

length = 11

The product of 10 and the difference between 8 and -9?

Answers

Hi there!  

»»————- ★ ————-««

I believe your answer is:  

170

»»————- ★ ————-««  

Here’s why:  

⸻⸻⸻⸻

[tex]\text{The phrase can be rewritten as:}\\\\10 * (8-(-9))\\---------------\\\rightarrow 8-(-9) = 8 + 9 = 17\\\\\rightarrow 10 * 17\\\\\rightarrow \boxed{170}[/tex]

⸻⸻⸻⸻

»»————- ★ ————-««  

Hope this helps you. I apologize if it’s incorrect.  

Silicone implant augmentation rhinoplasty is used to correct congenital nose deformities. The success of the procedure depends on various biomechanical properties of the human nasal periosteum and fascia. An article reported that for a sample of 10 (newly deceased) adults, the mean failure strain (%) was 24.0, and the standard deviation was 3.2.

Required:
a. Assuming a normal distribution for failure strain, estimate true average strain in a way that converys information about precision and reliability.
b. Predict the strain for a single adult in a way that conveys information about precision and reliability. How does the prediction compare to the estimate calculated in part (a)?

Answers

Solution :

Given information :

A sample of n = 10 adults

The mean failure was 24 and the standard deviation was 3.2

a). The formula to calculate the 95% confidence interval is given by :

[tex]$\overline x \pm t_{\alpha/2,-1} \times \frac{s}{\sqrt n}$[/tex]

Here, [tex]$t_{\alpha/2,n-1} = t_{0.05/2,10-1}$[/tex]

                       = 2.145

Substitute the values

[tex]$24 \pm 2.145 \times \frac{3.2}{\sqrt {10}}$[/tex]

(26.17, 21.83)

When the [tex]\text{sampling of the same size}[/tex] is repeated from the [tex]\text{population}[/tex] [tex]n[/tex] infinite number of [tex]\text{times}[/tex], and the [tex]\text{confidence intervals}[/tex] are constructed, then [tex]95\%[/tex] of them contains the [tex]\text{true value of the population mean}[/tex], μ in between [tex](26.17, 21.83)[/tex]

b). The formula to calculate 95% prediction interval is given by :

    [tex]$\overline x \pm t_{\alpha/2,-1} \times s \sqrt{1+\frac{1}{n}}$[/tex]

   [tex]$24 \pm 2.145 \times 3.2 \sqrt{1+\frac{1}{10}}$[/tex]

   (31.13, 16.87)

Please help!
Answers
A,B,C and D
The information is already in the chart
( ignore the charts below question 2.)

Answers

I believe the answer is B!

Hope this helped you! Please follow my account, thanks!

The answer is (B) ur welcome

A tank contains 9,000 L of brine with 18 kg of dissolved salt. Pure water enters the tank at a rate of 90 L/min. The solution is kept thoroughly mixed and drains from the tank at the same rate.
(a) How much salt is in the tank after t minutes?
(b) How much salt is in the tank after 20 minutes?

Answers

Let x(t) denote the amount of salt (in kg) in the tank at time t. The tank starts with 18 kg of salt, so x (0) = 18.

The solution is drained from the tank at a rate of 90 L/min, so that the amount of salt in the tank changes according to the differential equation

dx(t)/dt = - (x(t) kg)/(9000 L) × (90 L/min) = -1/100 x(t) kg/min

or, more succintly,

x' = -1/100 x

This equation is separable as

dx/x = -1/100 dt

Integrating both sides gives

∫ dx/x = -1/100 ∫ dt

ln|x| = -1/100 t + C

x = exp(-1/100 t + C )

x = C exp(-t/100)

(a) Using the initial condition x (0) = 18, we find

18 = C exp(0)   ==>   C = 18

so that

x(t) = 18 exp(-t/100)

(b) After 20 minutes, we have

x (20) = 18 exp(-20/100) = 18 exp(-1/5) ≈ 14.74

so the tank contains approximately 14.74 kg of salt after this time.

For the same random sample of adult women, with a sample mean height of x¯=64.3 inches and sample standard deviation of s=2.4 inches, use the Empirical Rule to determine the approximate percent of heights that lie between 59.5 inches and 69.1 inches.

Round your answer to the nearest whole number (percent).

Answers

Answer:

95%

Step-by-step explanation:

Mean , xbar = 64.3; standard deviation, s= 2.4

Using the empirical formula where ;

68% of the distribution is within 1 standard deviation from the mean ;

95% of the distribution is within 2 standard deviation from the mean

percent of heights that lie between 59.5 inches and 69.1 inches.

Number of standard deviations from the mean /

Z = (x - μ) / σ

(x - μ) / σ < Z < (x - μ) / σ

(59.5 - 64.3) / 2.4 < Z < (69.1 - 64.3) / 2.4

-2 < Z < 2

Thia is within 2 standard deviations of the means :

2 standard deviation form the mean = 95% according to the empirical rule.

Decompose -6x/(x+2)(x+8) into partial fractions.

Answers

The partial fraction expansion takes the form

-6x/((x + 2) (x + 8)) = a/(x + 2) + b/(x + 8)

Both factors in the denominator are linear, so the numerators in the corresponding partial fractions have degree 1 - 1 = 0 and are thus constants.

Combine the fractions on the right side into one with a common denominator, then set the numerators on both sides of the equation equal to each other:

-6x = a (x + 8) + b (x + 2)

Expand the right side and collect terms by powers of x :

-6x = (a + b) x + (8a + 2b)

It follows that

a + b = -6   and   8a + 2b = 0

==>   a = -2   and   b = 8

So we end up with

-6x/((x + 2) (x + 8)) = -2/(x + 2) + 8/(x + 8)

PLEASE HELP
Write the equation of the line that is perpendicular to the given segment and that passes through the point (-6, -3). A. 1 V=--x-3 2 B. 1 V=--X-6 2 C. y = 2x + 9 D. = 2x-6.​

Answers

Answer:

C

Step-by-step explanation:

The slope of the line will be (2) and the equation will be C

Find the measure of the incanted angle to the nearest degree

Answers

Answer:

15.4 degrees

Step-by-step explanation:

b= 53

h = 55

cos -¹( 53/53)= 15.4

poonam wants to invest in an account today
to have $4000 at the end of 8 years.
If she can invest at 4.25% Compounded
Semi-annually, how much does she need
to invest?

Answers

Answer:

2055.15

Step-by-step explanation:

A(1+r)^n=4000

A is the money that she need to invest

r is rate

n is the time( depend on monthly or yearly rate)

A(1+4.25%)^16=4000

A=2055.15

Determine what type of transformation is represented.



A. none of these
B. reflection
C. dilation
D. rotation

Answers

Answer:

The answer is "Option D"

Step-by-step explanation:

In a rotation, an item is rotated around with a known location. Clockwise or anticlockwise spinning is possible. Rotation centers are spherical geometry in space where rotation occurs. The direction of inclination is the indicator of the total rotation made. Rotary point refers to that part point of a figure around which it is revolved.

5+(-7)=
A-12
B
-2
с
2
D
12
E
none of these

Answers

Answer:

-2

Step-by-step explanation:

5 + (-7)

Since the 7 is larger than 5, the 7 will overpower the 5 in a way. So, all you do is subtract 7 and 5.

7 - 5 = 2

But the 7 has a negative with it (since it's larger), so you add the negative to the 2.

7 - 5 = -2

The answer will be -2.

Which of the following pairs of functions are inverses of each other?
A. f(x) = 5 + x and g(x) = 5 - x
B. f(x) = 2x -9 and g(x)=x+9/2
C. f(x) = 3-6 and g(x)=x+6/2
D. f(x)= x/3+4 and g(x) = 3x - 4​

Answers

The pair of functions that are inverses of each other is B. f(x) = 2x - 9 and g(x) = x + 9/2.

To determine if two functions are inverses of each other, we need to check if the composition of the functions results in the identity function, which is f(g(x)) = x and g(f(x)) = x.

Let's analyze the given options:

A. f(x) = 5 + x and g(x) = 5 - x

To check if they are inverses, we compute f(g(x)) = f(5 - x) = 5 + (5 - x) = 10 - x, which is not equal to x. Similarly, g(f(x)) = g(5 + x) = 5 - (5 + x) = -x, which is also not equal to x. Therefore, these functions are not inverses.

B. f(x) = 2x - 9 and g(x) = x + 9/2

By calculating f(g(x)) and g(f(x)), we find that f(g(x)) = x and g(f(x)) = x, which means these functions are inverses of each other.

C. f(x) = 3 - 6 and g(x) = x + 6/2

Similar to option A, we compute f(g(x)) and g(f(x)), and find that they are not equal to x. Hence, these functions are not inverses.

D. f(x) = x/3 + 4 and g(x) = 3x - 4

After evaluating f(g(x)) and g(f(x)), we see that f(g(x)) = x and g(f(x)) = x. Therefore, these functions are inverses of each other.

In summary, the pair of functions that are inverses of each other is B. f(x) = 2x - 9 and g(x) = x + 9/2.

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Your true height is 70.2 inches. A laser device at a health clinic that gives measurements to thenearest hundredth reads your height as 71.05 inches. A tape measure gives reading to the nearest haftinches gives your height as 69.5 inches. State which measurement is more precise and which measurementis more accurate and explain why.

Answers

Answer:

Accuracy = Tape measurement.

Precision = Laser measurement

Step-by-step explanation:

Given that :

True height, = 70.2 inches

Laser measured height = 71.05 (nearest hundredth)

Tape measured height = 69.5 - nearest half inch.

Accuracy simply means how close a measured value is to the true value of the measurement. ;

True height - tape measurement

70.2 - 69.5 = 0.7

True measurement - laser measurement :

|70.2 - 71.05| = 0.85

Fron the difference in the values, the measurement which is closer to the true height is the tape measurement.

However, in terms of detail in the measured value, the laser measure value is expressed to the nearest hundredth, hence giving it more precision over the tape measured value.

write fifty and two hundreds eight thousandths as a mixed decimal

Answers

Answer:

Pretty sure it's 0.528

Other Questions
Sweatshirts at the school store cost $30. They currently sell about 4 shirts per month. They have decided to decrease the price of the shirts. They found the for each each $1.50 decrease, they will sell 2 more shirts per month. How many decreases in prices will give the max value?A. 30B. 9C. 363D. 16.50 Risk acceptance is a natural part of driving. Risks are always present, and the compensation involves: Recognizing _____________________ errors. Making appropriate adjustments A driver often makes ________________ decisions in city traffic driving Studies indicate that drivers who do not wear safety belts tend to make more risks while driving than drivers wearing seat belts. Driving behavior is based on risk ___________________ rather than _________________ risk. Factors that drivers cannot control in risk management are: _____________________________________ _____________________________________ An internet provider states that, on average, the daily amount of time an adult spends on the internet is 4.5 hours. A sociologist studying the behaviors of internet consumers believes the average daily amount an adult spends on the internet is different than the amount stated by the internet provider. After completing a study, the sociologist found that the average daily amount of time an adult spends on the internet is 5.9 hours, on average. As the sociologist sets up a hypothesis test to determine if their belief is correct, what is their claim? a. The average daily amount of time an adult spends on the internet is different than 4.5 hours. b. The average daily amount of time an adult spends on the internet is different than 5.9 hours. c. Adults spend a majority of their time on the internet. d. 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