A congruent number can be defined as an integer that is equal to the area of a rational right triangle. Numbers (a, x, y, z, t) such that {x^2 + a y^2 = z^2 x^2 - a y^2 = t^2 auto right match are also known as congruent numbers. They are a generalization of the congruum problem, which is the case y = 1.
