Answer:
sum of interior angle of triangle is 180°
therefore, 81°+37°+X=180°
118°+X =180°
X=180°-118°
X=62°
k+x=180°
k+62°=180°
k=180°-62°
k=118°
hence proved
OR
the sum of 2 interior angle is equal to a exterior angle,so 81°+37°=k
118°=k
Hope it will help you.
