How Tall Is the Great Pyramid? The ancient Greek philosopher Thales of Miletus is reported...

How Tall Is the Great Pyramid? The ancient Greek philosopher Thales of Miletus is reported on one occasion to have visited Egypt and calculated the height of the Great Pyramid of Cheops by means of shadow reckoning. Thales knew that each side of the base of the pyramid was 252 paces and that his own height was 2 paces. He measured the length of the pyramid’s shadow to be 114 paces and determined the length of his shadow to be 3 paces. See the illustration. Using similar triangles, determine the height of the Great Pyramid in terms of the number of paces.

Source Diggins, Julie E, String Straightedge and Shadow: The Story of Geometry, 2003, Whole Spirit Press, http://wholespiritpress.com.