posted by ryan on .
This one is confusing me. please help
The diameter of a circle has endpoints P(–10, –2) and Q(4, 6).Find the center of the circle.Find the radius. If your answer is not an integer, express it in radical form. Write an equation for the circle.
Surely you can see that the center of the circle is the midpoint of any diameter.
the midpoint R = (P+Q)/2 = (-3,2)
the radius is half the diameter
d^2 = 14^2 + 8^2 = 196+64 = 260
r^2 = 65
(x+3)^2 + (y-2)^2 = 65