Answer:
1. a. If ∠8 is supplementary to ∠9, then line x and line y are parallel lines whereas line s is the transverse line.
b. ∠7 = ∠4, gives line x and line y are parallel and line s is the transverse line.
c. ∠9 is supplementary to ∠12, then line s and line t are parallel and line y is the transverse line.
d. ∠9 = ∠11 {Alternate angles}
That means line s and line t are parallel and line y is the transverse line.
Step-by-step explanation:
1. a. If ∠8 is supplementary to ∠9, then line x and line y are parallel lines whereas line s is the transverse line.
b. ∠7 = ∠4.
Now, ∠7 = ∠2 and ∠4 = ∠9.
So, ∠2 = ∠9 {Alternate angles}
Hence, line x and line y are parallel and line s is the transverse line.
c. ∠9 is supplementary to ∠12, then line s and line t are parallel and line y is the transverse line.
d. ∠9 = ∠11 {Alternate angles}
That means line s and line t are parallel and line y is the transverse line.
