An angle is formed when two lines meet at a point, which is called the vertex. The two lines are called the sides of an angle. Degree is a measure of the angle. The higher the degree, the more wide "open" the angle is. By definition, an angle that is 90 degrees is called a right angle, while an angle of 180 degrees is simply a straight line.
Angles can be designated in one of several ways:
- An angle can be designated by a letter
- An angle can be designated by using the vertex
- An angle can be designated by using the vertex and two points that lie on the sides of the angle
Below are several angles. Notice that several of them are the same, but because of different naming conventions, different angles are given different names.
