7.2 Exterior Angle Theorem

1. 7.2 Exterior Angle Theorem

2. Vocabulary Exterior Angle Theorem What You'll Learn You will learn to identify exterior angles and remote interior angles of a triangle and use the Exterior Angle Theorem. 1) Interior angle 2) Exterior angle 3) Remote interior angle

3. P 1 3 4 2 Q R Exterior Angle Theorem interior In the triangle below, recall that 1, 2, and 3 are _______ angles ofΔPQR. exterior Angle 4 is called an _______ angle of ΔPQR. linear pair An exterior angle of a triangle is an angle that forms a _________ with one of the angles of the triangle. In ΔPQR, 4 is an exterior angle at R because it forms a linear pair with 3. Remote interior angles ____________________ of a triangle are the two angles that do not form a linear pair with the exterior angle. In ΔPQR, 1, and 2 are the remote interior angles with respect to 4.

4. 1 2 3 4 5 Exterior Angle Theorem In the figure below, 2 and 3 are remote interior angles with respect to what angle? 5

5. X 1 2 3 4 Y Z Exterior Angle Theorem remote interior angles m4 = m1 + m2

6. Exterior Angle Theorem

7. X 1 2 3 4 Y Z Exterior Angle Theorem remote interior angles m4 > m1 m4 > m2

8. 74° 2 1 3 Exterior Angle Theorem Name two angles in the triangle below that have measures less than 74°. 1 and3 acute

9. Exterior Angle Theorem

10. ? x = y Exterior Angle Theorem The feather–shaped leaf is called a pinnatifid. In the figure, does x = y? Explain. 28° __ + 81 = 32 + 78 28 109 = 110 No! x does not equal y