Tolong banget please..

a.
x + 55 = 180
x = 180 - 55 = 125

b. 
x = 50 (trapesium sama kaki)
y = 90 (siku-siku)
z + 50 = 180
z = 180 - 50 = 130

c. 
z + 50 + 65 = 180
z = 180-50-65 = 65
y = z = 65
x + 100 + y = 180
x + 100 + 65 = 180
x = 180-100-65 = 15

d. 
x = 45 ( segitiga sama kaki)
z + 45 + x = 180
z + 45 + 45 = 180
z = 180 - 45 - 45 = 90
y + 40 + 90 = 180
y = 180 - 90 - 40 = 50