Math lesson plan · 8th grade (Year 9 in England) · 30 minutes
Volume of a cylinder
Geometry
CCSS 8.G.C.9England: KS3 Geometry and measuresEngland: GCSE Foundation Geometry and measures
Objective and success criteria
Students will: Volume of a cylinder.
- 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: Area of a circle; Volume of prisms
Leads to: Volume of a cone; Volume of spheres and hemispheres; Find a missing radius or height from a volume
Materials: Rulers and protractors, Squared or dotted paper, Shape cut-outs, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 4 min
- Quick retrieval from earlier learning (Area of a circle; Volume of prisms). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- A triangular prism has a triangular end with base 10 cm and height 10 cm. The prism is 4 cm long. What is its volume, in cm³? → 200Prompt: Volume of a prism = area of cross-section × length.
- A circle has diameter 20 m. Its area is kπ m². What is k? → 100Prompt: Find the radius first: half the diameter.
- A triangular prism has a triangular end with base 10 m and height 2 m. The prism is 15 m long. What is its volume, in m³? → 150Prompt: Volume of a prism = area of cross-section × length.
Hook · 3 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: Volume of a cylinder. Read the success criteria together.
I do: model it · 7 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: A cylinder has radius 3 cm and height 3 cm. Find its volume in cm³, to 1 decimal place.
- Step 1: π × 3² × 3 = 27π
- Step 2: ≈ 84.8 cm³
- Answer: 84.8
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 6 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- A cylinder has radius 5 cm and height 5 cm. Find its volume in cm³, to 1 decimal place. → 392.7Prompt: A cylinder is a prism with a circular cross-section.
- A cylinder has radius 8 m and height 10 m. Its volume is kπ m³. What is k? → 640Prompt: V = πr²h. Leave π as a symbol.
You do: independent practice · 7 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 6 questions are on the student sheet below, with answers in the key.
Exit ticket · 3 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- A cylinder has radius 5 cm and height 19 cm. Find its volume in cm³, to 1 decimal place. → 1492.3Prompt: A cylinder is a prism with a circular cross-section.
- A cylinder has radius 4 m and height 6 m. Its volume is kπ m³. What is k? → 96Prompt: V = πr²h. Leave π as a symbol.
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: Area of a circle.
- 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
- Move on to: Volume of a cone; Volume of spheres and hemispheres; Find a missing radius or height from a volume.
- 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-8.
Free lesson plan from eurekami.com/lesson-plan-builder