Question

10-13. A. Assuming that the sun’s rays are essentially parallel, determine the central angle of the circle if the angle passes through Alexandria and Syene. How did you find your answer?

Answer 1

We can relate the centra angle for the arc between Syene and Alexandria and the angle that makes the sun ray with the stick using the fact the alternate interior angles between parallels are congruent:

Then, the central angle for the arc between Syene and Alexandria is equal to the angle θ.