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Geometry ­ Sect. 1.5
G. SRT.7 / Math Pract. 2,3
Sect. 1.5 ­ Angle Relationships
Adjacent angles ­ lie in the same plane and have
the same vertex and a common side but no
common interior points.
1
1 and 2 are
adjacent angles
2
Linear pair ­ an adjacent pair of angles whose
non common sides are opposite rays.
2
1
1 and 2 form a
linear pair
Vertical angles ­ two non adjacent angles formed by intersecting lines.
2
3
1
4
Mr. VanKeuren / G.H.S. / 2014
1 and 3 and
2 and 4 are
vertical angles
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Geometry ­ Sect. 1.5
G. SRT.7 / Math Pract. 2,3
Ex.: Use the given figure to name each of the indicated items.
a. All of the adjacent angles.
6
7
b. All of the linear pairs.
c. All of the vertical angles.
Mr. VanKeuren / G.H.S. / 2014
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4
3
2
1
2
Geometry ­ Sect. 1.5
G. SRT.7 / Math Pract. 2,3
Angle pair relations ­
Vertical angles are congruent.
1
2
4
1 3
3
2 4
Complementary angles add to 90 .
D
1
or
50
40
C
2
1 and 2 are complementary
C and D are complementary
Supplementary angles add to 180 .
2
1
30
150
or
F
E
1 and 2 are supplementary
E and F are supplementary
Angles in a linear pair are supplementary.
1 and 2 in the last relationship example form a linear pair
and are supplementary angles.
Mr. VanKeuren / G.H.S. / 2014
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Geometry ­ Sect. 1.5
G. SRT.7 / Math Pract. 2,3
Note ­ It is important to remember to use the
information you are given. Do not presume
things exist or are true unless stated or proven. Pictures are not drawn to scale and
you must use definitions to determine relationships or conclusions.
Ex.: Find x and y so that AC and DF are perpendicular.
D
E
4y+2
A
B
2x­4 C
2x+6
G
F
Mr. VanKeuren / G.H.S. / 2014
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