Linear Pair

is a pair of adjacent angles whose noncommon sides form a straight angles (are opposite rays)

Vertical Angles

are angles adjacent to the same angle and forming linear pairs with it

Complementary Angles

two angles that have a sum of 90°

Supplementary Angles

two angles that have a sum of 180°

Theorem 4.1

all right angles are congruent

Theorem 4.2

if two angles are adjacent and supplementary, then they form a linear pair

Theorem 4.3

angles that form a linear pair are supplementary

Theorem 4.4

if one angle of a linear pair is a right angle, then the other angle is also a right angle

Theorem 4.5 - Vertical Angle Theorem

vertical angles are congruent

Theorem 4.6

congruent supplementary angles are right angles

Theorem 4.7- Angle Bisector Theorem

If ray AB bisects <CAD, then m< CAB=1/2m<CAD