Question

What is the radius of the circle whose equation is x2 + y2 = 9?


3
9
81

Answer 1

x2 + y2 = R^2

r^2 = 9
r = ?

Answer 2

is it 3?

Answer 3

Here's how you can check. If the radius is 3, then x=3 and y=0 should make a true number sentence. Does \[3^2+0^2=3^2\]?