Question

Complete the proof of the exterior angle theorem given angle 4 is an exterior angle of triangle ABC prove angle 1+ angle 2= angle 4

Answer 1

angle 1 +angle 2 + angle 3 =*180

angle 3+angle 4=*180

so,we can say,

angle 1+angle 2+angle 3 = angle 3+angle 4

i,e; angle 1+angle 2= angle 4 proved.

Explanation:

Answer 2

In the triangle ,1,2,3 are interior angles and 4 is the exterior angle , adjascent to 3
angle 1 +angle 2 + angle 3 =*180
angle 3+angle 4=*180
so,we can say,
angle 1+angle 2+angle 3 = angle 3+angle 4
i,e; angle 1+angle 2= angle 4 proved.