Download Geometry Lesson 1 By Lorraine Gordon Olde Towne Middle School

Geometry Lesson 1
By Lorraine Gordon
Olde Towne Middle School
3a: Locate and Identify angles formed
by parallel lines cut by a transversal
(e.g., adjacent, vertical,
complementary, supplementary,
corresponding, alternate interior, and
alternate exterior).
Transversal
• A line that intersects
two other lines in
different points is a
transversal
• Line N is a
Transversal
Transversal
• Transversals form 8
angles by bisecting
(cutting across) two
different lines. The two
lines this transversal is
bisecting are parallel.
• The angles that are
formed are adjacent,
vertical, complementary,
supplementary,
corresponding, alternate
interior, and alternate
exterior.
Vertical Angles
• Are formed by two
intersecting lines and are
opposite each other.
Vertical angles are
congruent (have the same
measurement)
• Vertical angles form an X.
• Vertical angles are across
from each other or nose to
nose
• <1&<4, <2&<3, <5&<8,
<6 &<7 are vertical
angles.
Adjacent Angles
• Adjacent angles share a
vertex and a side but no
points in their interior.
• Adjacent angles are side
by side or back to back
• <1&<2, <1&<3, <2&<4,
<3&<4, <5&<6, <6&<8,
<5&<7, <7&<8 are all
adjacent pairs of angles.
Supplementary Angles
• Two angles that add
together to form a 180
degree angle.
• <a&<b are
supplementary
because the sum of
these two angles
equals 180 degrees
(forms a straight line)
Complementary Angles
• The sums of the
measures of two
angles is 90 degrees.
• <AOC & <COB add
together to make
<AOB which is 90
degrees.
Corresponding Angles
• Lie on the same side of
the transversal and in
corresponding positions.
• <EFB &<FGD are
corresponding angles.
• They are also congruent.
• Name the other
corresponding angles.
Alternate Exterior Angles
• Located on the
outside of the parallel
lines and on opposite
sides.
• <H & <B and <G &
<A are alternate
exterior angles.
• Alternate exterior
angles are congruent
Alternate Interior Angles
• Are in the interior (inside)
of a pair of lines and on
opposite sides of the
transversal.
• <E & <C and <F & <D
are alternate interior
angles
• Alternate interior angles
are congruent
• They form a Z pattern.
Wrap up
1. Name two pairs of
adjacent angles.
2. Name a pair of
corresponding angles.
3. <1 & <2 are
supplementary or
complementary?
4. Name a pair of
corresponding angles.
5. Name a pair of alternate
interior angles.
6. Name a pair of alternate
exterior angles