Area of a circle

1. Nov 7, 2003

repugno

Hello all. Where can I find proof that the area of a circle can be calculated using the formula &pi;r2? Any response will be greatly appreciated, thank you.

2. Nov 7, 2003

StephenPrivitera

I believe it can be done using a limit process. Cut the circle into n equal triangles and take the limit as n goes to infinity.

3. Nov 7, 2003

HallsofIvy

Staff Emeritus
And, of course, the area of a circle of radius R, with center at the origin of a coordinates system is the integral
&int;-RR2&radic;(R2- x2)dx. That gives &pi;R2 as the area.