Honors Geometry Section 1.3 part2

Special Angle Pairs

Let’s consider several special pairs of angles.

Complementary angles are two angles whose measures have a

sum of 90 degrees.

Each angle is called a __________ of the other.

complement

Supplementary angles are two angles whose measures have a

sum of 180 degrees.

Each angle is called a ___________ of the other.

supplement

Example 1: Complete the chart.

27 11745 45

)90( x )180( x

18018573 xx

375.191558

180258

xxx

875.114125.65

BmAm

Example 3: The measure of an angle is 10 less than three times the measure of its complement. Find the measure of both angles.

supplement x-180compliment90

angle

x

x x 10)90(3 x

652604

103270

xx

xx

25 & 65

Two angles are adjacent if they have the same vertex and share a

side in common.

A linear pair is two angles which are adjacent and whose noncommon

sides form a straight line.

Postulate 1.3.5: Linear Pair Postulate

If two angles form a linear pair, then they are supplementary.

Example 4: Name all angles that form a linear pair with .BMA

AMEBMD

71951957

1801571803186

x

xx

xx186 x

3x