Mathematics · Grades 4–8
Geometry: units and dimensions
Perimeter uses length units, area uses square units and volume uses cubic units.
Understand the idea
Match dimensions
Perimeter uses length units, area uses square units and volume uses cubic units.
Read the labels
Check whether a given length is a radius, diameter, height or sloping side.
Examples and reasoning
Which unit is appropriate for the area of a classroom floor?
m²
m²
Which unit is appropriate for the volume of a box?
cm³
cm³
Check your understanding
A rectangle is 7 cm by 4 cm. Find its perimeter in cm.
A rectangle is 7 cm by 4 cm. Find its area in cm².
Can two rectangles have the same area but different perimeters? Give an example.
A circle has diameter 18 cm. Its radius is
- 324 cm
- 36 cm
- 9 cm
- 18 cm
Answers and marking notes
Answers and marking notes
- 22
2 × (7 + 4) = 22
- 28
7 × 4 = 28
- Yes. A 6 by 2 rectangle and a 4 by 3 rectangle both have area 12, but perimeters 16 and 14.
Yes. A 6 by 2 rectangle and a 4 by 3 rectangle both have area 12, but perimeters 16 and 14.
- 9 cm
9 cm
Learning preview · teacher review required. Grade bands are approximate, not official curriculum alignment.