In the figure above, secant AB is perpendicular to radius OC. Chord CF
cuts AB at E and AC cuts circle O at D. If CE = 4, EF = 6 and CD = 3, find
AD.
George Polya's 1945 book "How to Solve It, A new aspect of Mathematical Method", is a book describing methods of problem solving. It suggests the following steps when solving a mathematical problem: (1) First, you have to understand the problem. (2) After understanding, then make a plan. (3) Carry out the plan. (4) Look back on your work. How could it be better?