Question

GEOMETRY HELP PLEASE!!!!!!! I REALLY NEED HELP FAST!!!!!!! I WILL GIVE BRAINLIEST!

2. Complete the proof of the exterior angle theorem.
Given: ∠4 is an exterior angle of Δ ABC.
Prove: m∠1 + m∠2 = m∠4

Answer 1

2. Definition of linear pair

3. Linear pair theorem

4. Definition of supplementary angles

5. m<1 + m<2 + m<3 = 180

6. Substitution property of equality

7. m<1 + m<2 + m<4

7. Subtraction property of equality

Answer 2

The exterior angle theorem, m∠1 + m∠2 = ∠4 is proved.

From given figure,

In triangle ABC, the sum of all three angles is equal to 180 degree.

    $\angle1+\angle2+\angle3=180............(1)$

In given diagram angle 3 and 4 form linear pair.

                   $\angle3+\angle4=180........(2)$

From equation 1 and 2

         $\angle1+\angle2+\angle3=\angle3+\angle4\\\\\angle1+\angle2=\angle4$

Hence proved.

Learn more:

https://brainly.com/question/25143301