Depth of a Crater on the Moon The depths of unknown craters on the moon can be approximated by comparing the lengths of their shadows to the shadows of near-
by craters with known depths. The crater Aristillus is 11,000 ft deep, and its shadow
was measured as 1.5 mm on a photograph. Its companion crater, Autolycus, had a
shadow of 1.3 mm on the same photograph. Use similar triangles to determine the
depth of the crater Autolycus. (Source: Webb, T., Celestial Objects for Common
Telescopes, Dover Publications, 1962.)