Answer:
8
Step-by-step explanation:
<u>Area of a circle = πr^2</u>
64π / π = πr^2 / π
sqrt(64) = sqrt(r^2)
8 = r
Answer: 8
The equation is 
The solved equation is 11
First, we must add 13 on both sides

The answer to the equation is 
Answer:
r = 13
Step-by-step explanation:
Hypotenuse is the side opposite to 90 degree angle, so hypotenuse is r.
Also, with respect to the angle given, the side "12" is the opposite.
So we have opposite side to angle and we need hypotenuse. Which trigonometric ratio related opposite with hypotenuse? It is SINE.
So we can write:

Rounded to nearest whole number, r = 13
I would say a cause they have the same curves
Let C and d be the circumference and diameter of a circle, respectively. Then
C = πd
so that
π = C/d = C/12