Question

In triangle ABC, find angle A + angle B , if theexterior angle of is 135°

Answer 1

The exterior angle of C is 135
Therefore C=180-135
C=45
According to angle sum property.
A+B+C=180
A+B=180-45
A+B=135
Thus Sum of two angles is always equal to the exterior angle of the third angle.

Answer 2

if exterior angle is 135°
than c=180-135
=45
a+b=180-45
=135