Question

If (9, 1) and (1,9) are the endpoints of a diameter of a circle, what is the equation of the circle?

Answer 1

(x - 5)² + (y - 5)² = 32

Explanation:

Centre = midpoint of the diameter

(h,k) = (9+1)/2, (9+1)/2 = (5,5)

Radius² = [(9-5)² + ((1-5)²]

= 16 + 16 = 32

Equation:

(x - 5)² + (y - 5)² = 32