Step-by-step explanation:
A^ = 40° ( given)
considering ABD triangle
B^ = D ^ = (180 - 40)÷ 2 (angles in a triangle, AB = AD)
considering BDC triangle
D^ = C^ = x ( BD = DC)
then m2^ = 180- 2x
x = 110° ( on straight line )
m2^ = 180 - 220°
= - 40°
it can't be negative .. there's some issue with the given figure .
