The Book of Measures

The work known as The Book of Measures (Sefer ha-middot), probably written by Abraham Ibn Ezra, survives in only a single Hebrew manuscript and a single medieval Latin translation. This book treats arithmetic (often citing “the wise men of India”) and geometry, offering an approximation for pi and rules for calculating the area of triangles, quadrilaterals, and various three-dimensional shapes. This book appears to be closely related to Ibn Ezra’s The Book of Number. These excerpts set out some of the basic goals of this work, the author’s discussion of zero and its symbol, some discussion of division, and methods for calculating area and the height of large items. The text in italics appears only in the Latin translation.