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Angle Relationships. Supplementary angles Two angles whose sum is 180 ° Complementary angles Two angles whose sum is 90° . Vertically opposite angles Non-adjacent angles formed when two lines cross <AEB and <DEC are vertically opposite angles What is the other pair?.
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Supplementary angles • Two angles whose sum is 180° Complementary angles • Two angles whose sum is 90°
Vertically opposite angles • Non-adjacent angles formed when two lines cross • <AEB and <DEC are vertically opposite angles • What is the other pair?
Sum of the Interior Angles in a Triangle • Draw any size triangle on a piece of paper and cut it out. • Label the angle a, b, and c. • Tear off angles b and c. • Line them up with angle a. What do you see?
The sum of the interior angles of a triangle is always 180°.
Transversal • A line that crosses two other lines or line segments
Corresponding angles • Angles either both above or both below two lines on the same side of a transversal • If the lines are parallel, corresponding angles are congruent
Interior angles • Angles between two lines on the same side of a transversal • If the lines are parallel, interior angles are supplementary
Alternate interior angles • Angles between two lines on either side of a transversal • If the lines are parallel, alternate interior angles are congruent
Find the measures of 1) <EHB 2) <FHG 3) <EHG Example 1
Find the measure of the unknown angle (x). Support your answer with geometric reasoning. Example 2
Find the measure of the unknown angle (x). Support your answer with geometric reasoning. Example 3
Find the measure of the unknown angles (x and y). Support your answer with geometric reasoning. Example 4
Classwork • Page 431-432, #1 and 3