Question

Complete the proof of the exterior angle theorem. Given: ∠4 is an exterior angle of △ABC. Prove: m∠1+m∠2=m∠4 Answer: Statement Reason 1. ∠4 is an exterior angle of △ABC. 1. 2. ∠3 and ∠4 form a linear pair. 2. 3. ∠3 is supplementary to ∠4. 3. 4. m∠3+m∠4=180° 4. 5. 5. Triangle Sum Theorem 6. m∠1+m∠2+m∠3=m∠3+m∠4 6. 7. 7.

Answer 1

Answer: Attached Below.

Explanation:

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Answer 2

Explanation:

Statement Reason

1. ∠4 is an exterior angle of ΔABC Given

2. ∠3 and ∠4 form a linear pair Linear pair property

3. ∠3 is supplementary to ∠4 Straight line property

4. m∠3+m∠4=180° ∠3 is supplementary to ∠4

5. m∠1+m∠2+m∠3=180° Triangle sum theorem

6.m∠1+m∠2+m∠3= m∠3+m∠4 Statement 4 and 5

7. m∠1+m∠2=m∠4 Subtraction property