c. 190-c. 120 B.C.

Greek mathematician and astronomer who wrote a number of works, including the so-called "Book XIV" of the Elements. In this book, often mistakenly included with the original writings of Euclid (c. 325-c. 250 B.C.), Hypsicles improved on Apollonius's (c. 262-c. 190 B.C.) approach to problems involving a dodecahedron and an icosahedron inscribed in the same sphere. Hypsicles is also credited with works on polygonal numbers, regular polyhedra, and arithmetic progressions. The latter appears in his On the Ascension of Stars, the first astronomical text to divide the zodiac into 360 degrees.