A circle has the equation Find the radius of the circle. Then calculate the area of the circle. (Leave in terms of .)

Question

 

Answer 1

The general formula for a circle with center (h,k) is

(x-h)²+(y-k)² = r²

So 16 is r² , so the radius is √16 = 4

A=πr² = π·4² = 16π square units