Step by step
The question
Question: find out if the two lines are parallel.
The alternate angles are 135° and 125°.
1 Name the angle pair
A line crosses two other lines.
It is called a transversal.
Our two angles are between the lines, on opposite sides of the transversal: alternate angles.
Together they make a Z shape.
2 Use the parallel test
Parallel lines make alternate angles equal.
And if they are equal, the lines are parallel.
135° and 125° are not equal.
135 ≠ 125
Careful!
For alternate angles we ask: are they equal?
Careful: alternate: equal, not adding to 180°
So the lines are not parallel.
Answer: = not parallel
If we carry the lines on, they would meet.
Look at the picture: the top line is turned.
Let's look back.
First: name the angle pair.
Last: use the parallel test.
Answer
Answer: = not parallel