Answer:
y = 38
Step-by-step explanation:
The sum of the 3 angles in a triangle = 180°
Consider the angles in the large outer triangle, then
x + 46 + 78 = 180
x + 124 = 180 ( subtract 124 from both sides )
x = 56
Consider the 3 angles in the smaller inner triangle, then
y + x + 86 = 180 , that is
y + 56 + 86 = 180
y + 142 = 180 ( subtract 142 from both sides )
y = 38
