Perimeter, Area & Volume — Year 7 Revision Notes
These notes cover perimeter, the area of rectangles, triangles and compound shapes, and the volume of cuboids, with a focus on using the correct units.
Perimeter and area of basic shapes
Perimeter is the total distance around a shape. The area of a rectangle is length × width, and the area of a triangle is ½ × base × height, using the perpendicular height.
Key Facts & Formulas
- Area of rectangle = l × w
- Area of triangle = ½ × b × h
- Perimeter = sum of all sides
Tips
- Use the perpendicular height of a triangle, not the slant side.
- Area is in square units (cm²), perimeter in length units (cm).
Compound shapes
A compound shape can be split into rectangles and triangles. Find the area of each part and add them together. Work out any missing lengths from the information given.
Key Facts & Formulas
- Total area = sum of part areas
Tips
- Draw the split clearly with a dashed line.
- Label every length before you calculate.
Volume of a cuboid
Volume measures the space inside a solid. For a cuboid it is length × width × height, and the answer is in cubic units such as cm³.
Key Facts & Formulas
- Volume of cuboid = l × w × h
Tips
- Volume is in cubic units (cm³, m³).
- Make sure all three measurements are in the same unit first.
Revision Checklist
- I can find the perimeter of a shape
- I can find the area of rectangles and triangles
- I can find the area of a compound shape
- I can find the volume of a cuboid using the correct units
Frequently Asked Questions
What units do I use for area and volume?
Area uses square units such as cm², because it covers a surface. Volume uses cubic units such as cm³, because it fills a space.
Build strong foundations in Perimeter, Area & Volume
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