circle p has a center

Question

if circle P has a center at (-1,3) and (3,6)is on the circle what is the diameter of the circle P

Answer 1

The diameter is 2r, where r is the radius.  Find the radius from

 

r² = (x - x_c)² + (y - y_c)²

 

where (x_c,y_c) is the center, and (x,y) is any point on the circle.

 

r² = [3 - (-1)]² + (6 - 3)²