Math lesson plan · 6th grade (Year 7 in England) · 30 minutes
Area of shapes made from rectangles and triangles
Geometry
CCSS 6.G.A.1England: KS3 Geometry and measuresEngland: GCSE Foundation Geometry and measures
Objective and success criteria
Students will: Area of shapes made from rectangles and triangles.
- 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 composite rectilinear shapes; Area of triangles
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 · 4 min
- Quick retrieval from earlier learning (Area of composite rectilinear shapes; Area of triangles). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- An L-shape is made by cutting a 4 m by 4 m rectangle from the corner of a 9 m by 6 m rectangle. What is the area of the L-shape, in m²? → 38Prompt: Find the area of the big rectangle.
- A garden is made of two rectangles: 3 m × 2 m and 3 m × 6 m. What is the total area, in m²? → 24Prompt: Find the area of each rectangle.
- An L-shape is made by cutting a 4 m by 3 m rectangle from the corner of a 11 m by 8 m rectangle. What is the area of the L-shape, in m²? → 76Prompt: Find the area of the big rectangle.
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 shapes made from rectangles and triangles. 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: An L-shaped room is a 15 m by 7 m rectangle with a 9 m by 3 m rectangle missing from one corner. What is its floor area, in m²?
- Step 1: 15 × 7 = 105
- Step 2: 9 × 3 = 27
- Step 3: 105 − 27 = 78 m²
- Answer: 78
- 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.
- An L-shaped room is a 16 m by 10 m rectangle with a 8 m by 3 m rectangle missing from one corner. What is its floor area, in m²? → 136Prompt: Find the area of the big rectangle.
- A house-shaped sign is a 6 cm wide, 3 cm tall rectangle with a triangle on top. The triangle has the same base and is 2 cm tall. What is the total area, in cm²? → 24Prompt: Split the shape into a rectangle and a triangle.
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 house-shaped sign is a 12 cm wide, 6 cm tall rectangle with a triangle on top. The triangle has the same base and is 3 cm tall. What is the total area, in cm²? → 90Prompt: Split the shape into a rectangle and a triangle.
- An L-shaped room is a 13 m by 6 m rectangle with a 3 m by 3 m rectangle missing from one corner. What is its floor area, in m²? → 69Prompt: Find the area of the big rectangle.
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 composite rectilinear shapes.
- 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-6.
Free lesson plan from eurekami.com/lesson-plan-builder