Answer:
x + z = 180
x = 180 - z
y + z +10 = 180
y = 170 - z
w + z - 13 = 180
w = 193 - z
x + y + w = 180⁰
180 - z + 170 - z + 193 - z = 180
-3z = -363
z = 121⁰
