(a)x+90=180(Linear pair)
x=90
z+30=180,z=150,y=90+30(Exterior angle)
y=120
x+y+z=90+120+150=360
(b)Sum of all measure of all interior angles of quad=360
a+60+80+120=360
a=100
x+120=180(Linear pair)
x=60
y+80=180,y=100
z+60=180,z=120
w+100=180,w=80
Sum of measure of all interior angles=x+y+z+w=60+100+120+80=360