An elementary theorem in geometry whose name means ``asses' bridge.'' The theorem states that the Angles at the base of an Isosceles Triangle (defined as a Triangle with two legs of equal length) are equal.
See also Isosceles Triangle, Pythagorean Theorem
References
Dunham, W. Journey Through Genius: The Great Theorems of Mathematics. New York: Wiley, p. 38, 1990.