Maximum Length

Two circles intersect at points C and D. Point A lies on the circle at the left, point B lies on the circle at the right. Find the positions of A and B (on their given circle) such that segment AB is at its maximum possible length, and points A, C, and B are collinear.


                      Circle 1                                      Circle 2


Connect points A, B, and D.
What can you say about the angles of 
the triangle ABD as A and B chnage
their positions?

Check answer