Question -
Answer -
In the given problem, the exterior angles obtained on producing the base of a triangle both ways are 
and 
. So, let us draw ΔABC and extend the base BC, such that:
Here, we need to find all the three angles of the triangle.
Now, since BCD is a straight line, using the property, “angles forming a linear pair are supplementary”, we get
Similarly, EBC is a straight line, so we get,
Further, using angle sum property in ΔABC
Therefore,