# Lines r and s are parallel Lines r and s are parallel.

You already know that when any two lines intersect, vertical angles are always congruent and adjacent angles are always supplementary. You also know that when two parallel lines are intersected by a transversal, corresponding angles are congruent.

1.

1 is congruent to 3 because they are _________________ angles.

2.

1 is supplementary to 4 because they are ________________ angles.

3.

1 is congruent to 5 because they are ___________________ angles.

4.

So 5 would also be ___________________ to 4.

Try it:

1.

List all angles that are congruent to 1._____________________________

2.

List all angles that are supplementary to 1.__________________________

3.

Are 2 and 6 congruent or supplementary?

4.

Are 2 and 5 congruent or supplementary?

5.

Suppose the measure of 2 is 140 o

, what is the measure of 8?

6.

Suppose the measure of 1 is (x + 15) o

and the measure of 8 is 130 , then what is the value of x?

7.

Suppose the measure of 1 is (3x + 25) o

and the measure of 5 is (x + 75) o

, then what is the value of x?