Acute Isosceles Triangles 1) must have three angles under 90 degrees 2) must have at most two different angles 3) must have at most two different side lengths 4) equilateral triangle is a special case
Right Isosceles Triangles 45/45/90 1) must have 1 90 degree angle 2) must have 2 45 degree angles
Obtuse Isosceles Triangles 1) must have 1 angle greater than 90 degrees 2) must have two angles less than 45 degrees