Download Parallel Lines, Perpendicular Lines, and Angles

Parallel Lines, Perpendicular Lines, and Angles
Complementary Angles
Angles in which the sum of their measures is 90o.
Example
30o
60o
Supplementary Angles
Angles in which the sum of their measures is 180o.
Example
120o
60o
Linear Pair
Two angles that share a vertex, a side, and make a straight line are called a
linear pair. The sum of the measure of the two angles is 180o.
Example
110o
A
D
70o
B
C
∠ABD and ∠CBD are a linear pair.
Perpendicular Lines
Two lines are perpendicular if they intersect at a 90o angle. Perpendicular lines
are usually notated with a red box.
m
n
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Parallel Lines Intersected by a Transversal
When two parallel lines (in the same plane) are intersected by a transversal in
the same plane, the following relationships exist between the eight angles
formed.
8 7
5 6
4
1
3
2
m
n
Corresponding Angles – share the same “location” in their quadrants. ∠1 and
∠5 are corresponding since they are both at the lower left of the angles.
Corresponding angles are always congruent.
Interior Angles – angles in between the two parallel lines (∠3, ∠4, ∠5, ∠6).
Exterior Angles – angles on the outside of the two parallel lines (∠1, ∠2, ∠7,
∠8)
Alternate Angles – angles on opposite side of transversal
Consecutive Angles – angles on the same side as the transversal
Vertical Angles – angles that are created by two intersecting lines. They share
a vertex, but no sides. (∠2 and ∠4) Vertical angles are always congruent.
Alternate Interior Angles (AIA) – Angles inside the parallel lines and opposite
sides of transversal. (∠3 and ∠5) AIA are always congruent.
Alternate Exterior Angles (AEA) – Angles outside the parallel lines and on
opposite sides of transversal. (∠1 and ∠7) AEA are always congruent.
Consecutive Interior Angles (CIA) - Angles inside the parallel lines and on the
same side of transversal. (∠3 and ∠6) CIA are always supplementary.
Consecutive Exterior Angles (CEA) - Angles outside the parallel lines and on
the same side of transversal. (∠2 and ∠7) CEA are always supplementary.
© LaurusSoft, Inc.