Answer:
x = 81, y = 68 and z = 99
Explanation:
The external angle of a triangle is equal to the sum of the 2 opposite interior angles.
z is an exterior angle, thus
z = 63 + 36 = 99
x and z form a straight angle and are supplementary, so
x + z = 180, that is
x + 99 = 180 ( subtract 99 from both sides )
x = 81
The sum of the 3 angles in a triangle = 180°, thus
z + y + 13 = 180, that is
99 + y + 13 = 180
112 + y = 180 ( subtract 112 from both sides )
y = 68