Question

Circle A’s circumference is 3 times the value of Circle B’s Area. Find Circle B’a radius.

Answer 1

(side note: your formula C = 2πr^2 is incorrect, it should be C = 2πr)

Answer:

r = 9

Step-by-step explanation:

First let's find the circumference of Circle A. To use the formula we need radius. Since we have a diameter just divide by 2 to get radius. 27 / 2 = 13.5

Now plug that into C = 2πr: 2π*(13.5) = 27π

The question says that the area of circle B is 3x this value, so Circle B's area must be: 27π * 3 = 81π

Now plug that into A = πr^2 and solve for r:

$81\pi=\pi r^{2}\\81=r^{2}\\\sqrt{81}=r\\9=r$

(edited to correct a brain fart)