Answer:
a = 97° , b = 19°
Explanation:
the exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.
(a)
a is an exterior angle of the triangle , then
a = 40° + 57° = 97°
(b)
57° is an exterior angle of the triangle , then
b + 38° = 57° ( subtract 38° from both sides )
b = 19°