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Unformatted text preview: 7-3 The Exterior Angle Theorem
A) Definition a. Exterior Angle i. If C is between A and D, then C BCD is an exterior angle of ABC ii. Every triangle has six exterior angles B) Definition a. Remote Interior Angles i. A and B are remote interior angles of the exterior angles BCD and ACE C) Theorem 7-2 (The Exterior Angle Theorem) a. An exterior angle of a triangle is greater than each of its remote interior angles b. Proof i. Given: ABC , If C is between A and D ii. Prove: BCD B Statement Reason 1) Introduce E, the midpoint of BC 1) Midpoint theorem 2) On the ray opposite to EA introduce 2) Point-Plotting Th. the point F, such that EF = EA 3) Introduce FC 4) 5) 6) 7) 8) 9) 3) Line Postulate 4) 5) 6) 7) 8) 9) D) Corollary 7-2.1 a. If a triangle has one right angle, then its other angles are acute b. ...
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This note was uploaded on 05/16/2011 for the course ALGEBRA 098 taught by Professor Johnson during the Spring '09 term at Grand Valley State University.
- Spring '09