We present an elementary prescription based on the rational secant method for generating all the integral triangles containing a given angle of rational cosine. This is a direct generalization of the ancient problem of finding all the Pythagorean triples. As an example, we discuss a specific equation studied by Diophantus of Alexandria, which turns out to be equivalent to the problem of finding all the integral triangles containing a 60 ∘ angle. The material developed here is elementary enough for inclusion in undergraduate courses and advanced high school courses.