Question

If the radius of a circle is 8 inches find the radius of a circle whose area is four times as large?

Answer 1

16 inches

Explanation:

`A = pi * r^2`
`=> A = pi * 8^2`
`=> A = 64pi`

`A' = 4A`

`A' = pi * r'2`

`pi * r'^2 = 4(64pi)`

`=> r'^2 = 256`

`=> r' = 16`