Question

Point Y is on a circle and point P lies outside the circle such that \overline{PY} is tangent to the circle. Point A is on the circle such that segment \overline{PA} meets the circle again at point B. If PA = 15 and PY = 9, then what is AB?

unitsize(2 cm);pair A, B, P, Y;Y = dir(130);A = dir(20);B = dir(180);P = extension(Y, Y + rotate(90)*(Y), A, B);draw(Circle((...