Question

What is the standard equation of a circle at the origin?
A. x2 - y2 = r2
B. x2 + y2 = r2
C. x2 + y2 = r
D. x2 - y2 = r

Answer 1

B

Answer 2

how do you figure that ?

Answer 3

usually in a circle equation (x-h)^2+(y-k)^2= r^2
r is radius and h and k are usually points in your case origon is (0,0)
leaving you with x^2+y^2=r^2