Answer:
Step-by-step explanation:
The sum of the angles in a triangle is 180 degrees.
Considering the inner triangle, it means that
63 + 36 + x = 180 degrees
99 + x = 180
x = 180 - 99
x = 81 degrees.
The sum of the angles on a straight line is 180 degrees. Considering the base of the triangle, it means that
x + z = 180
81 + z = 180
z = 180 - 81 = 99 degrees
Recall: The sum of the angles in a triangle is 180 degrees. Therefore,
z + y + 13 = 180
81 + y + 13 = 180
94 + y = 180
y = 180 - 94
y = 86 degrees
