The circle below is centered at the origin and has a radius of 10. What is its equation?

Answer:
x²+y² = 100
Step-by-step explanation:
Equation for circle of radius r that is centered at (h,k):
(x-h)² + (y-k)² = r²
In your case, h=k=0 and r=10.
x²+y² = 100