# PARALLEL LINES CUT BY A TRANSVERSAL

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PARALLEL LINES CUT BY A TRANSVERSAL

DEFINITIONS PARALLEL TRANSVERSAL ANGLE VERTICAL ANGLE
CORRESPONDING ANGLE ALTERNATE INTERIOR ANGLE ALTERNATE EXTERIOR ANGLE

DEFINITIONS SUPPLEMENTARY ANGLE COMPLEMENTARY ANGLE CONGRUENT

Parallel lines cut by a transversal
2 1 3 4 6 5 7 8

Parallel lines cut by a transversal
2 1 3 4 6 5 7 8 < 1 and < 2 are called SUPLEMENTARY ANGLES They form a straight angle measuring 180 degrees.

Parallel lines cut by a transversal
2 1 3 4 6 5 7 8 < 2 and < 3 < 3 and < 4 < 4 and < 1 < 5 and < 6 Name other supplementary pairs: < 6 and < 7 < 7 and < 8 < 8 and < 5

Parallel lines cut by a transversal
2 1 3 4 6 5 7 8 < 1 and < 3 are called VERTICAL ANGLES They are congruent m<1 = m<3

Parallel lines cut by a transversal
2 1 3 4 6 5 7 8 < 2 and < 4 < 6 and < 8 Name other vertical pairs: < 5 and < 7

Parallel lines cut by a transversal
2 1 3 4 6 5 7 8 < 1 and < 5 are called CORRESPONDING ANGLES They are congruent m<1 = m<5 Corresponding angles occupy the same position on the top and bottom parallel lines.

Parallel lines cut by a transversal
2 1 3 4 6 5 7 8 < 2 and < 6 < 3 and < 7 Name other corresponding pairs: < 4 and < 8

Parallel lines cut by a transversal
2 1 3 4 6 5 7 8 < 4 and < 6 are called ALTERNATE INTERIOR ANGLES They are congruent m<4 = m<6 Alternate Interior on on the inside of the two parallel lines and on opposite sides of the transversal.

Parallel lines cut by a transversal
2 1 3 4 6 5 7 8 < 3 and < 5 Name other alternate interior pairs:

Parallel lines cut by a transversal
2 1 3 4 6 5 7 8 < 2 and < 8 < 1 and < 7 Name other alternate exterior pairs:

TRY IT OUT 2 1 3 4 6 5 7 8 120 degrees The m < 1 is 60 degrees.
What is the m<2 ? 120 degrees

TRY IT OUT 2 1 3 4 6 5 7 8 60 degrees The m < 1 is 60 degrees.
What is the m<5 ? 60 degrees

TRY IT OUT 2 1 3 4 6 5 7 8 60 degrees The m < 1 is 60 degrees.
What is the m<3 ? 60 degrees

TRY IT OUT 120 60 60 120 120 60 60 120

TRY IT OUT 2x + 20 x + 10 What do you know about the angles?
Write the equation. Solve for x. SUPPLEMENTARY 2x x + 10 = 180 3x + 30 = 180 3x = 150 x = 30

TRY IT OUT 3x - 120 2x - 60 What do you know about the angles?
Write the equation. Solve for x. ALTERNATE INTERIOR 3x = 2x - 60 x = Subtract 2x from both sides Add 120 to both sides

WEBSITES FOR PRACTICE Ask Dr. Math: Corresponding /Alternate Angles
Project Interactive: Parallel Lines cut by Transversal

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