Math lesson plan · 7th grade (Year 8 in England) · 30 minutes
Area of a circle
Geometry
CCSS 7.G.B.4England: KS3 GeometryEngland: GCSE Foundation Geometry
Objective and success criteria
Students will: Area of a circle.
- 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: Circumference of a circle; Whole-number exponents
Leads to: Volume of cylinders, cones and spheres; Arc length and sector area; Area and perimeter of semicircles and quarter circles
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 (Circumference of a circle; Whole-number exponents). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Evaluate 2⁴. → 16Prompt: Write it out: 2 × 2 × 2 × 2
- A circle has radius 3 ft. Give its circumference in terms of π: it is kπ ft. What is k? → 6Prompt: C = 2πr.
- Evaluate 3⁵. → 243Prompt: Write it out: 3 × 3 × 3 × 3 × 3
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: Area of a circle. 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 circle has diameter 14 cm. Its area is kπ cm². What is k?
- Step 1: r = 14 ÷ 2 = 7
- Step 2: A = π × 7² = 49π cm²
- Answer: 49
- 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 circle has diameter 10 m. Its area is kπ m². What is k? → 25Prompt: Find the radius first: half the diameter.
- What is the area of a quarter circle with radius 7 ft? Round to 1 decimal place. → 38.5Prompt: Find the area of the whole circle first.
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 circle has diameter 10 yd. Its area is kπ yd². What is k? → 25Prompt: Find the radius first: half the diameter.
- What is the area of a semicircle with radius 3 cm? Round to 1 decimal place. → 14.1Prompt: Find the area of the whole circle first.
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: Circumference 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 cylinders, cones and spheres; Arc length and sector area; Area and perimeter of semicircles and quarter circles.
- 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