Mensuration is about measuring shapes — perimeter, area, surface area and volume.
Key formulae
Rectangle area $= l \times w$ · Triangle area $= \tfrac12 bh$ · Circle area $= \pi r^2$ · Cuboid volume $= l \times w \times h$
Example: a cuboid $4 \times 3 \times 2$ has volume $24$; a circle of radius 7 (using $\pi=\tfrac{22}{7}$) has area $154$.
Remember
- Area in square units; volume in cubic units.
- Circle area $= \pi r^2$; circumference $= \pi d$.