Question

the equation of a circle centered at the origin is x^2+y^2=64.what is the radius of the circle?
A.32
B.8
C.4
D.64

Answer 1

EQUATION OF A CIRCLE = (x-h)² + (y-k)² =r²

In this case, since the center of the cercle is in O, then h=0 & k=0

x²+y² = 64

Answer 2

the answer is 8, i thought it was 4 but my apex class said 8 was the correct answer.