What is a true statement about a 45-45-90 triangle?

I will list a couple of facts about a 45-45-90 triangle because the more the merrier!

A 45-45-90 triangle is an isosceles right triangle

In a 45-45-90 triangle, the hypotenuse is  times as long as one of the legs.

A 45-45-90 triangle is half of a square (with the same side length as the legs)

The answer is part a: use