Let A, B, C be points on circle O such that AB is a diameter, and CO is perpendicular to AB. Let P be a point on OA, and let line CP intersect the circle again at Q. If OP = 20 and PQ = \(6\), find r^2, where r is the radius of the circle.
Here's the same problem solved by heureka with only PQ = 7 instead of 6
https://web2.0calc.com/questions/pls-help-i-don-t-know-how-to-do-this
