Math lesson plan · 7th grade (Year 8 in England) · 45 minutes
Use vertically opposite angles
Geometry
CCSS 7.G.B.5England: KS3 Geometry and measuresEngland: GCSE Foundation Geometry and measures
Objective and success criteria
Students will: Use vertically opposite angles.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Vertical, complementary and supplementary angles
Leads to: the next skill in this area.
Materials: Rulers and protractors, Squared or dotted paper, Shape cut-outs, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Vertical, complementary and supplementary angles). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- What is the complement of 85°? → 5Prompt: Complementary angles add up to 90°.
- Two angles on a straight line are (2x + 11)° and 145°. Find x. → x = 12Prompt: Angles on a straight line add up to 180°.
- What is the supplement of 146°? → 34Prompt: Supplementary angles add up to 180°.
Hook · 5 min
- Show a photo of a building, a tile pattern or a road sign and ask what shapes and angles students can spot.
- Share the objective: Use vertically opposite angles. Read the success criteria together.
I do: model it · 10 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Two straight lines cross. One of the angles is 62°. What is the angle vertically opposite it?
- Step 1: Opposite angles are equal: 62°
- Answer: 62
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Two straight lines cross. One of the angles is 125°. What is the angle vertically opposite it? → 125Prompt: Vertically opposite angles are equal.
- Two vertically opposite angles are (4x + 20)° and 92°. Find x. → 18Prompt: Vertically opposite angles are equal, so write an equation.
You do: independent practice · 10 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Two vertically opposite angles are (3x − 5)° and 79°. Find x. → 28Prompt: Vertically opposite angles are equal, so write an equation.
- Two straight lines cross. One of the angles is 148°. What is the angle vertically opposite it? → 148Prompt: Vertically opposite angles are equal.
Watch out for
- Thinking a square turned on its corner is no longer a square.
- Reading the wrong scale on a protractor.
Support and stretch
Support
- Review first: Vertical, complementary and supplementary angles.
- Use concrete materials: rulers and protractors.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/math/grade-7.
Free lesson plan from eurekami.com/lesson-plan-builder