Angles at a point, on a line and in parallel lines
Angle rules are like a set of keys — once you know which one fits, missing angles unlock in seconds.
Part of your national curriculum
- Geometry and measures: Apply the properties of angles at a point, on a straight line, vertically opposite angles, and angles in parallel lines
Lesson overview
What you'll learn in this lesson
Apply the properties of angles at a point, on a straight line, vertically opposite angles, and angles in parallel lines
Key learning points
- • The core rules
- • Worked example
- • Parallel lines example
This lesson at a glance
- 24 minutes
- 17 parts to scroll through
- 3 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 17
Visual introductionPicture this
Angles at a point, on a line and in parallel lines
Angle rules are like a set of keys — once you know which one fits, missing angles unlock in seconds.
In a nutshell
Apply the properties of angles at a point, on a straight line, vertically opposite angles, and angles in parallel lines
Learning cycle
Part 2 of 17
Learning cycle 1 of 2
Part 1 · The core rules
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 17
Learn
The core rules
Angles on a straight line sum to 180°. Angles around a point sum to 360°. Vertically opposite angles (formed by two crossing lines) are equal. Angles in parallel lines cut by a transversal give equal alternate and corresponding angles.
Reset break
Part 4 of 17
Pause
That's sitting 1 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Explore the idea
Part 5 of 17
Learn
Worked example
Two angles on a straight line are x and 65°. Since they sum to 180°: x = 180 - 65 = 115°.
Quick check
Part 6 of 17
Quick check
Part 7 of 17
Reset break
Part 8 of 17
Pause
That's sitting 2 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 9 of 17
Learning cycle 2 of 2
Part 2 · Parallel lines example
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 17
Learn
Parallel lines example
A transversal crosses two parallel lines, making a corresponding angle of 72° with the first line. The corresponding angle at the second line is also 72°, since corresponding angles are equal.
Quick check
Part 11 of 17
Quick check
If a corresponding angle is 72°, what is the matching corresponding angle on the other parallel line?
Reset break
Part 12 of 17
Pause
That's sitting 3 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 13 of 17
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 14 of 17
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
____ on a straight line sum to 180°.
____ opposite angles (formed by two crossing lines) are equal.
Two angles on a ____ line are x and 65°.
Challenge round
Part 15 of 17
Game · Recall cards
Angles on a straight line total:
Card 1 of 4
Mastery quiz
Part 16 of 17
Marked quiz
End of lesson quiz: Angles at a point, on a line and in parallel lines
4 questions, marked with the reasoning shown. No timer.
1. Angles on a straight line total:
2. Vertically opposite angles are:
3. Co-interior angles between parallel lines total:
4. Two angles on a straight line are x and 65°. What is x?
Lesson round-up
Part 17 of 17
Lesson round-up
Ready when you are
Quiz score
Not sat
Games
Not played
Points this lesson
0
Best run
0 in a row
Luna: 0 out of 3 on the practice checks. Only if you feel up to it — one more?
Ask LunaPart 1 of 17 · Watch & discover
How this is going
- Not looked at yet
Apply the properties of angles at a point, on a straight line, vertically opposite angles, and angles in parallel lines