PROVE ANGLE PAIR
RELATIONSHIPS
Section 2.7
In this section…
 We will continue to look at 2 column proofs
 The proofs will refer to relationships with angles.
 We will also use the facts about angle pairs to find
measures of angles. (Algebra)
Recall these facts about angles
 Right angles have a measure of 90˚
 Obtuse angles have angle measures greater than 90˚
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and less than 180 ˚
Acute angles have angle measures greater than 0 ˚
and less than 90˚
Straight angles have a measure of 180˚
Complementary angles are 2 angles whose sum
equals 90˚
Supplementary angles are 2 angles whose sum equals
180˚
Supplementary angles aren’t necessarily a linear pair
Angles cont.
 Perpendicular lines have an angle measure of 90˚
 Linear pairs are two angles that are supplementary and
share a common side.
 Vertical pairs are angles created by two intersecting
lines that are opposite each other. They also have the
same angle measure.
Angles Cont.
 Adjacent angles are angles that share a common
interior side.
Common
side
“New” Theorems
Identify Congruent Pairs of Angles
<1 and <2, <1 and <3,
and <2 and <3
Identify Congruent Pairs of Angles
<1 & <2, <1 & <3, <1 & <4,
<2 & <3, <2 & <4, <3 & <4
Identify Congruent Pairs of Angles
<1 & <3, <4 & <2
Find the measures of the angles and the values
of x and y.