# Geometry

posted by
**Emily**
.

How can I tell if a triangle is a 30, 60 90 triangle or a 45 45 90? What are the characteristics?

A 45-45-90 triangle has two equal angles (and sides). It is an isoceles right triangle, in other words. It is easy to tell by looking that a 30-60-90 triangle does not have two equal angles.