Question

Find y in the following diagrams.

Answer 1

acute angle obtuse angle

Answer 2

1) 80+57+5x-6=180
x=49/5
2)45+45+4y+18=180
y=18
3) 31+11x+11+39=180
x=9
4)60+40+y=180
y=80
x+y=180(because it is a straight line)
x+80=180
x=100