Question

What has to be true in order to be sure a triangle is a right triangle?

Answer 1

The two sides other than the right angle have to add up to 90 degrees.

Explanation:

For a triangle to be a right triangle the two sides other than the right angle must add up to 90 degrees and they have be equal, so each must equal 45 degrees in order for it to be a right triangle. :)

Answer 2

Right angle

Explanation:

All right triangles have to have a 90 degree right angle. That's what makes it a right triangle.