An angle is formed by the union of two non-collinear rays that have a common endpoint. This endpoint is the vertex of the angle, and the two rays become the sides of this angle. These two rays can form different types of angles.
The different types of angles formed are acute, right, obtuse and reflex angles. A reflex angle is greater than 180 degrees but less than 360 degrees. In math, the convention for naming angles is either to use the vertex point or by using three points. Two of these points lie on either angle sides, and the third is the vertex. For example, an angle having point F on one angle side, point G on the other side and the vertex H can be named angle H, angle FHG or angle GHF.