Answer:
11) Alternate Interior Angles
x=6
12) Vertical Angles
x=8
13) Consecutive Interior Angles
x=5
14) Corresponding Angles
x=9
Step-by-step explanation:
11) Alternate Interior Angles
18x+7=115
18x=115-7
18x=108
x=108÷18
x=6
12) Vertical Angles
16x-8=15x
16x-15x=8
x=8
13) Consecutive Interior Angles
21x-5+80=180
21x+75=180
21x=180-75
21x=105
x=105÷21
x=5
14) Corresponding Angles
10x-3=87
10x=87+3
10x=90
x=90÷10
x=9
