**Section Four**

__Pair of Angles__

Adjacent angles: are two angles in the same plane with a common vertex and a common side, but no common interior points.

Linear pair: is a pair of adjacent angles whose noncommon sides are opposite rays.

Complementary and Supplementary Angles:

Complementary: are two angles whose sums have a measure of 90 degrees.

Supplementary: are two angles whose measures have a sum of 180 degrees.

Vertical Angles: are two nonadjacent angles formed by two intersecting lines.