Perimeter and area · Grade 5
In Grade 5 you get fluent with: area of rectangles with a formula and compound shapes.
Perimeter is the distance all the way round a shape; area is the amount of flat space it covers, measured in square units. Knowing the area formulas for rectangles, triangles, parallelograms and trapeziums lets you work out compound shapes too.
Key facts
- Rectangle: area = length × width; perimeter = 2 × (length + width).
- Compound shapes: split into rectangles (or subtract a missing piece). Use the same units throughout.
Worked examples
Example 1
Find the area of this L-shape. All corners are right angles; lengths are in cm.
Answer: 55 cm²
Example 2
A lawn 12 m by 8 m has a path 1 m wide all round it. Find the area of the path.
Answer: 44 m²