The Ruins of Persepolis

There are two columns in the ruins of Persepolis left standing upright; one is 70 feet above the plane, and the other 50 feet. In a straight line between these stands an ancient small statue, 5 feet in height, the head of which is 100 feet from the summit of the taller column, and 80 feet from the top of the shorter column.  Required the distance between the tops of the two columns.

National Arithmetic, Benjamin Greenleaf, 1843

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