Draw a circle and one of its diameters, . Choose any point P ≠ A or B on that circle and d...

Draw a circle and one of its diameters, . Choose any point P ≠ A or B on that circle and draw segments and. Carefully measure ∠APB with a protractor. What did you find? Try the experiment several times with different locations for P to see if the phenomenon persists. What theorem in geometry does this experiment reveal?

*See Corollary A to Theorem 1, Section 4.5.