## Angle Addition Postulate

Help and definitions

First some definitions.

A __ __**line**ar pair is a pair of adjacent angles that are supplementary (which
means together they form a straight **line**).

A __vertical pair __is formed when two lines cross. They are
sometimes called opposite angles. They are always congruent to one
another.

Example:

Angle 1 and angle 2 are vertical angles. Angle 1 measures 14x + 17 and angle
2 measures 10x + 41. Find x and the measure of angle 1.

Since these are equal to one another:

14x + 17 = 10x + 41

-10x -10x

4x + 17 = 41

-17 -17

4x = 24

x = 6

Angle 1 = 14(6) + 17 = 101

CHECK!

Did Angle 2 come out the same?

Angle 2 = 10(6) + 41 = 101