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3 years ago

8

Rhianna painted a circle on a mural in her classroom. The circle has a radius of 5 inches. What is the area of the circle? (Use

3.14 for .)

1 answer:

Elis [28]3 years ago

6 0

Answer:

A =78.5 in^2

Step-by-step explanation:

The area of the circle is given by

A = pi r^2

A = pi * r^2

A = 25 pi

Using 3.14 for pi

A = 25 (3.14)

A =78.5 in^2

You might be interested in

7400 dollars is placed in an account with an annual interest

Anastasy [175]

Answer:

17

Step-by-step explanation:

We have the following equation for compounding annual interest

AV=PV(1+i)ⁿ

We have

19200=7400(1+.06)ⁿ

Solve for n

divide both sides by 7400

2.594=(1.06)ⁿ

then use the following rule for exponents

$x^y=z\\log_xz=y$

which means that

$log_{1.06}2.594=n$

Solve and get

16.362

which rounds to 17

6 0

3 years ago

Can somebody help me with this please?

Svetach [21]

Multiply both sides by -4/7
$x = 40 \times ( \frac{ - 4}{7} ) \\ x = \frac{ - 160}{7}$

7 0

3 years ago

postnew [5]

$2 \frac{5}{8} \div 2 \frac{1}{2}$
Change the mixed fractions to improper fractions.
To do this, multiply the whole number part by the denominator. Add that to the numerator. Then write the result on top of the denominator.

You would now have:
$\frac{21}{8} \div \frac{5}{2}$
Change the division sign to a multiplication sign by turning the second fraction upside down.
That is,
$\frac{21}{8} \times \frac{2}{5}$

The answer is:
$\frac{42}{40}$

This can be simplified to:
$\frac{21}{20}$

8 0

3 years ago

Twin brothers, Billy and Bobby, can mow their grandparent’s lawn together in 63 minutes. Billy could mow the lawn by himself in

Pepsi [2]

Answer:

<h2>140 minutes</h2>

Step-by-step explanation:

this problem focuses on the combined work rate

both can finish the work under 63 minute

let bobby mow the lawn in x minute

Billy will then mow the lawn in x-25 minutes

Let the completed job = 1 (a mowed lawn)

we can now apply the combined work formula for the two boys as

$\frac{63}{x}+\frac{63}{x-25}=1$

multiplying through by x(x-25 )we have

$63(x-25)+63x= x(x-25)$

open bracket we have

$63x-1575+63x= x^2-25x$

rearranging and collecting like terms we have

$0=x^2-25x-63x-63x+1575 \\\\0=x^2-151x+1575 \\\\x^2-151x+1575=0$

we can now use the quadractic formula

$x=\frac{-b\frac{+}{} \sqrt{b^2-4ac} }{2a}$

a= 1

b= -151

c= 1575

$x=\frac{-(-151)\frac{+}{} \sqrt{151^2-4*1*1575} }{2*1}$

$x=\frac{-(-151)\frac{+}{} \sqrt{22801-6300} }{2} \\\\x=\frac{-(-151)\frac{+}{} \sqrt{16501} }{2} \\\\x=\frac{-(-151)\frac{+}{} 128.45}{2} \\\\$

$x=\frac{-(-151)+128.45}{2} \\\\\x=\frac{279.45}{2} \\\\x=139.72 \\\\\\x=\frac{-(-151)-128.45}{2}\\\\x=\frac{151-128.45}{2}\\\\x=\frac{22.55}{2}\\\\x=11.27$

the first answer x= 139.72 approximately 140 minutes mins is correct for Bobby's time

let us check

$\frac{63}{140}+\frac{63}{140-25}=1\\\\\\0.45+\frac{63}{115} =1\\\\0.45+0.5478=1\\0.997 =1$

we can see that the solution approximates to 1

8 0

3 years ago

The volume of this sphere is 904.32 cubic inches. What is the surface area of this sphere?

andrew-mc [135]

Answer:

A = 4 pi R^2 V = 4/3 pi R^3

A / V = 3 / R

Also, R = (3 * V / 4 * pi)^1/3 = (3 * 904.32 / (4 * pi))^1/3 = 6 in

So A = 3 / 6 * V = 1/2 * 904.32 = 452.16 in^2

8 0

3 years ago