Right angle
From Wikipedia, a free encyclopedia written in simple English for easy reading.
A right angle is an angle of 90 degrees. If you draw a straight line and then another one that crosses it, in such a way that all angles have the same size, the result is a picture with four right angles. The top of the letter T is at right angles to the vertical line. Walls of buildings are usually at right angles to the floor. Two things that are at right angles are called "perpendicular".
A simple right angle can be made by folding a piece of paper twice.
