In the family of special angles in Geometry, we come across many angles beside acute, obtuse, right, straight and other. In special angle, we will study about supplementary and complementary angles. Moreover vertical opposite angles, adjacent angles, interior and exterior all comes in the category of special angles.

**Complementary Angles:**If the sum of two angles formed is 90 degrees, which means that if we add together two angles, we get the pair of Perpendicular Lines, then they are called complementary angles.**Supplementary Angles:**If the sum of two angles formed is 180 degrees, which means that if we add together two angles, we get the straight line, then the pair of angles is supplementary.**Vertical Opposite Angles:**If we have two Intersecting Lines, then the pair of opposite angles in the cross (X) so formed are called vertical opposite angles. The pair of vertical opposite angles, when the two lines intersect is always equal. So if one angle is known, the another angle measure will also be same.**Adjacent Angles:**If we have two angles combined together such that on joining them we get a Straight Line as the result, then the pair of angles is called a linear pair of angles. We say that the angles which have one common vertex and one common arm such that the common arm lies between the two uncommon arms, then we say that the angles are adjacent pair of angles.**Interior Angles:**The angles inside the transversal that cuts two Parallel Lines are called interior angles. The interior angles on the opposite side of the transversal are called interior alternate angles and that on the same side of the transversal are called interior consecutive angles. If the lines are parallel then the interior alternate angles are equal.**Exterior Angles:**The angles outside the transversal that cuts two parallel lines are called exterior angles. The exterior angles on the opposite side of the transversal are called exterior alternate angles and that on the same side of the transversal are called exterior consecutive angles.