Same place, other crossing
Corresponding angles sit in the same position at the two crossings.
Look for the twin
A transversal makes four angles at each line it crosses. Look at ∠1, the top-left angle at the first line.
Which angle at the second line is in the same position as ∠1?
What this lesson covers
The idea
A transversal forms one set of four angles with each of the two lines it crosses; angles in the same position in the two sets are called corresponding angles.
Look for the twin
A transversal makes four angles at each line it crosses. Look at ∠1, the top-left angle at the first line.
Which angle at the second line is in the same position as ∠1?
- ∠5, the top-left angle
- ∠7, the bottom-right angle
- ∠8, the bottom-left angle
Find the twin
One angle is lit. Tap the angle in the same position at the other line.
Corresponding angles
At each line the transversal makes four angles. Angles in the same position at the two lines are called corresponding angles.
A transversal forms one set of four angles with each of the two lines it crosses. Angles in the same position in the two sets are called corresponding angles.
- At l | Same position at m
- ∠1 (top left) | ∠5
- ∠2 (top right) | ∠6
- ∠3 (bottom right) | ∠7
- ∠4 (bottom left) | ∠8
Notes
A transversal forms one set of four angles with each of the two lines it crosses. Angles in the same position in the two sets are called corresponding angles.
Check yourself
Which angle is the corresponding angle of ∠7?
Two angles are in the same position at the two crossings of a transversal. What are they called?
Which of these is a pair of corresponding angles?
How many pairs of corresponding angles does a transversal make with two lines?
Answer: 4
The four positions (top left, top right, bottom right, bottom left) each give one pair: ∠1 and ∠5, ∠2 and ∠6, ∠3 and ∠7, ∠4 and ∠8.
- ∠5. ∠5 is also at m. Corresponding angles are at different lines.
- ∠3 — correct. Yes! ∠7 is the bottom-right angle at m. The bottom-right angle at l is ∠3.
- ∠1. ∠1 is the top-left angle at l, but ∠7 is bottom right. The position is not the same.
- Vertically opposite angles. Vertically opposite angles are at the same crossing, across from each other.
- Corresponding angles — correct. Yes! Angles in the same position in the two sets are corresponding angles.
- A linear pair. A linear pair is two neighbouring angles at one crossing that add up to 180°.
- ∠2 and ∠6 — correct. Yes! ∠2 is the top-right angle at l and ∠6 is the top-right angle at m.
- ∠2 and ∠4. They are at the same crossing, across from each other: vertically opposite angles.
- ∠3 and ∠5. ∠3 is bottom right but ∠5 is top left. They are not in the same position.