Math lesson plan · 5th grade (Year 6 in England) · 60 minutes
Vertically opposite angles
Geometry
CCSS 7.G.B.5England: Y6 Geometry
Objective and success criteria
Students will: 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: Missing angles on a straight line and around a point
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 · 6 min
- Quick retrieval from earlier learning (Missing angles on a straight line and around a point). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Four angles meet at a point: 118°, 38°, 135° and x. Find x. → 69Prompt: Angles around a point add up to 360°.
- On a straight line there are three angles: 40°, x and x (the two x angles are equal). Find x. → 70Prompt: Angles on a straight line add up to 180°.
- Three angles sit on a straight line: 43°, 41° and y. Find y. → 96Prompt: A straight line is half a turn.
Hook · 6 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: Vertically opposite angles. Read the success criteria together.
I do: model it · 12 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 24°. What is the angle vertically opposite it?
- Step 1: 24°
- Answer: 24
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 12 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 137°. What is the angle vertically opposite it? → 137Prompt: Vertically opposite angles are equal.
- Two lines cross, making four angles. One angle is 42°. What is the sum of the other two angles that are neither this angle nor the one opposite it? → 276Prompt: Each of the other two angles is 180° minus the given angle.
You do: independent practice · 17 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 · 7 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Two lines cross, making four angles. One angle is 145°. What is the sum of the other two angles that are neither this angle nor the one opposite it? → 70Prompt: Each of the other two angles is 180° minus the given angle.
- Two straight lines cross. One of the angles is 70°. What is the angle next to it (on the same straight line)? → 110Prompt: 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: Missing angles on a straight line and around a point.
- 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-5.
Free lesson plan from eurekami.com/lesson-plan-builder