Answer:
119°
Explanation:
the angles of a triangle make 180° (so does a straight line) therefore
180 (triangle) = a + c + 51
to find c:
180 (straight line) = 112 + c
c = 180 - 112
c = 68°
now we have
180 (triangle) = a + 68 + 51
to find a:
a = 180 - (68 + 51)
a = 180 - 119
a = 61°
to find b:
180 (straight line) = 61 + b
b = 180 - 61
b = 119°