Which of the following is the equation of a circle with center (-5, 2) and radius of 6?

Question

Which of the following is the equation of a circle with center (-5, 2) and radius of 6?

(x + 5)2 + (y - 2)2 = 6

(x - 5)2 + (y + 2)2 = 6

(x + 5)2 + (y - 2)2 = 36

(x - 5)2 + (y + 2)2 = 36

Answer 1

The formula for a circle with center (h,k) and radius r is:
(x - h)² + (y - k)² = r²

This comes directly from the Pythagorean theorem.

So in your example (h = -5, k = 2, r = 6)

(x - (-5))² + (y - 2)² = 6²
(x + 5)² + (y - 2)² = 36

This matches with the 3rd answer.

Answer 2

The formula is (x minus the x-number) squared plus (y minus the y-number) squared equals the radius squared