This document discusses properties of different types of triangles: - Isosceles triangles have two sides of equal length, with the third side being the base. Angles opposite equal sides are also equal. - Equilateral triangles have all three sides of equal length and all three interior angles of equal measure (60 degrees each). - Right triangles have one 90 degree angle. The hypotenuse-leg theorem states that if the hypotenuse and one leg are equal in two right triangles, then the triangles are congruent.