The figure shows a circle in the coordinate plane. The center of the circle is the point A(h,k). The point B(x,y) is a point on th

The figure shows a circle in the coordinate plane. The center of the circle is the point A(h,k). The point B(x,y) is a point on the circle. Triangle ABC is a right triangle, with point C the vertex of the right angle. The variable r represents the radius of the circle.