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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).
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Geometry Lesson 1By Lorraine GordonOlde 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).
A line that intersects two other lines in different points is a transversal Line N is a Transversal 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 • Name two pairs of adjacent angles. • Name a pair of corresponding angles. • <1 & <2 are supplementary or complementary? • Name a pair of corresponding angles. • Name a pair of alternate interior angles. • Name a pair of alternate exterior angles