Chapter 7: Angle facts and parallel lines
Angle diagrams are chains of reasons: each value should follow from a named fact.
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
- • Core facts
- • Parallel lines
- • Write the reason
This lesson at a glance
- 30 minutes
- 14 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 14
Watch first
Chapter 7: Angle facts and parallel lines
An English teaching video on this topic from mathantics. Watch it, then scroll down for the lesson.
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 14
Learning cycle 1 of 2
Part 1 · Core facts
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 14
Learn
Core facts
Angles on a straight line total 180°, around a point total 360°, and vertically opposite angles are equal.
Explore the idea
Part 4 of 14
Learn
Parallel lines
When a transversal crosses parallel lines, corresponding and alternate angles are equal; co-interior angles total 180°. Arrow markings are essential evidence that lines are parallel.
Quick check
Part 5 of 14
Quick check
Angles on a straight line total:
Reset break
Part 6 of 14
Pause
That's sitting 1 of 2 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.
Quick check
Part 7 of 14
Quick check
Vertically opposite angles are:
Learning cycle
Part 8 of 14
Learning cycle 2 of 2
Part 2 · Write the reason
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 9 of 14
Learn
Write the reason
Do not merely calculate. State, for example, x = 68° because alternate angles between parallel lines are equal.
Quick check
Part 10 of 14
Quick check
Co-interior angles between parallel lines total:
Challenge round
Part 11 of 14
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 12 of 14
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
____ on a straight line total 180°, around a point total 360°, and vertically opposite angles are equal.
Mastery quiz
Part 13 of 14
Marked quiz
End of lesson quiz: Chapter 7: Angle facts and parallel lines
3 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:
Lesson round-up
Part 14 of 14
Lesson round-up
Ready when you are
Quiz score
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Games
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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 LunaDo the work
Your written work for this lesson
This is the part you'd do in your book at school. Pick the pieces below, write here or on paper, and photograph anything you draw or work out.
The cost of a school trip
A school is planning a trip to a wildlife park. The coach costs £480 however many people go. Entry costs £9.50 for each pupil and each adult goes free. The school says every pupil must pay the same amount, and the trip must not lose money.
If 60 pupils go, the coach works out at £8 each, so the total for each pupil is £17.50. If only 40 pupils go, the coach works out at £12 each, so the price rises to £21.50. The teacher explains that the coach is a fixed cost and the entry is a cost per person — which is why the price per pupil changes when the number changes.
The school decides to charge £20 and to use anything left over for a second trip later in the year.
Written for Good Learning Co.
Reading questions
- Work out the total cost of the trip if 50 pupils go.
- Show why the price per pupil falls when more pupils go, using numbers.
- At £20 each, how many pupils must go before the trip makes money? Show your working.
Working out
Working outDo the practice questions on paper, showing every step — not just the answer. Mark them yourself and circle anything you got wrong.
10–15 questions
Worked example, explained
WritingCopy one question out and write underneath, in words, why each step works.
1 question, 4–5 sentences
Problem in words
Working outWrite your own real-life problem that uses today's method, then solve it.
1 problem + solution
Saved as you type.
Part 1 of 14 · Watch & discover
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Apply the properties of angles at a point, on a straight line, vertically opposite angles, and angles in parallel lines
