medea66 wrote:If area of circle = pi r squared, how do you get 8pi?

If a square is inscribed in a circle .. the diagonal of the square will be the diameter of the circle.

Area of the square = 16
hence S = 4

Diagonal of a square is sqrt 2* side

thus the diagonal is sqrt 2*4

hence the radius of ths circle is 1/2* (sqrt2*4)

thus Radius = sqrt2*2

Area of the circle is pi*r^2

therefore its pi* (2rt2)^2
= 8pi

hope it helps..

I get it.