Area & Perimeter
5 minQuiz at the end
Perimeter
Perimeter is the total distance around the outside of a shape.
| Shape | Formula |
|---|---|
| Rectangle | 2(l + w) |
| Square | 4s |
| Triangle | a + b + c |
| Circle (circumference) | 2Οr or Οd |
Rectangle 8cm Γ 5cm: 2(8 + 5) = 26cm
Area
Area is the amount of space inside a shape. Measured in square units (cmΒ², mΒ²).
| Shape | Formula |
|---|---|
| Rectangle | l Γ w |
| Square | sΒ² |
| Triangle | Β½ Γ base Γ height |
| Parallelogram | base Γ height |
| Trapezium | Β½(a + b) Γ h |
| Circle | ΟrΒ² |
Triangle, base 10cm, height 6cm: Β½ Γ 10 Γ 6 = 30cmΒ²
Circle, radius 7cm: Ο Γ 7Β² = 153.86cmΒ²
Trapezium, parallel sides 5cm and 9cm, height 4cm: Β½(5 + 9) Γ 4 = Β½ Γ 14 Γ 4 = 28cmΒ²
Composite Shapes
Divide complex shapes into simpler ones, calculate each area, and add (or subtract) as needed.