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4.2 Angles of Triangles. Objectives: *Apply the Angle Sum Theorem. *Apply the Exterior Angle Theorem. Mrs. S. Williams. Angle Sum Theorem. X. The sum of the measures of the angles of a triangle is 180. W + X + Y = 180. W. Y. Exterior Angle Theorem.
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4.2 Angles of Triangles Objectives: *Apply the Angle Sum Theorem. *Apply the Exterior Angle Theorem. Mrs. S. Williams
Angle Sum Theorem X • The sum of the measures of the angles of a triangle is 180. • W + X + Y = 180 W Y
Exterior Angle Theorem • The measure of an exterior angle of a triangle is equal to the sum of the measures of the two remote interior angles. 1 = 2 + 3 * 2 and 3 are remote interior angles. 3 2 1
Ex. Angle Sum Theorem 82° • Find the missing angle measures. 28° 1 2 63° 3
Ex. Exterior Angle Sum Theorem 3 • Find the measure of each numbered angle in the figure. 2 1 120° 4 5 50° 56° 78°