What is the area of a circle that has a circumference of 42 inches ?

D. 140.4 in²

Step-by-step explanation:

We are given the circumference.  The formula for circumference is

C = πd     where d is the diameter and C is the circumference.

We are given C = 42, so we have...

42 = πd  

Solving for d gives us...

42/π = d  

The formula for area of a circle is

A = π(r²)     where A is the area, and r is the radius

The radius is half of the diameter, so we divide 'd' by 2 to get the radius...

r = d/2 = (42/π)/2 = 21/π

The area of the circle is...

A = π(21/π)²

 A = π(441/π²)

    A = 441/π

       A = 140.3746598

             A = 140.4 in²

x=30

step-by-step explanation:

question 1 is 8, question 2 is 9, question 3 is 24

step-by-step explanation:

now, the numbers they give you at the top are the key. from there, you just have to plug and chug! let's try 1, 2, and 3!

key: a=3, b=5, c=6

1. a+5

remember, a=3, so we plug that in to get 3+5=8

2. 15-c

c=6, so we plug that in to get 15-6=9

3. 4b

b=6, so we plug it in to get 4*6=24

time to try the rest on your own! if you put the answers below in a comment, i'll check them for you!