Question

What is the radius of the circle who’s equation is x^2 + y^2 = 9

Answer 1

r=3

Explanation:

• The equation of a circumference is
  `(x-a)^2+(y-b)^2=r^2`.
• Then , in this case
  `r^2=9`, and then to know the value of r we just simply have to calculate the square root of 9, which is 3.