Menelaus of Alexandria (born ca. 70; died ca. 140) was a mathematician and astronomer, the first to recognize geodesics on a curved surface as natural analogs of straight lines.

Life

Although very little is known about Menelaus's life, it is supposed that he lived in Rome, where he probably moved after having spent his youth in Alexandria. He was called Menelaus of Alexandria by both Pappus and Proclus, and a conversation of his with Lucius, held in Rome, is recorded by Plutarch.

Plutarch also mentions, in his work Almagest, astronomical observations made by Menelaus in Rome on the 14th January in the year 98. One of these observations was on the occultation of the star Beta Scorpii by the moon.

Works

Sphaerica is the only book that has survived, in an Arabic translation. Composed of three books, it deals with the geometry of the sphere and its application in astronomical measurements and calculations. The book introduces the concept of spherical triangle (figures formed of three great circle arcs, which he named "trilaterals") and proves Menelaus theorem (an extension to spherical triangles of a previously known result).

Bibliography

Among the lost books are:

• On the calculation of the chords in a circle, composed of six books and
• Elements of geometry, composed of three books.

External links

• Menelaus of Alexandria
• Menelaus' Theorem Interactive proof with animation and key concepts by Antonio Gutierrez from "Geometry Step by Step from the Land of the Incas"