Chapter 10.2 (Mathematics 5)

Volume of Cubes and Cuboids using the Formula

Volume of a cube using the formula

In groups of five:

  1. Use 1 cm cubes to make a larger cube as shown.
  2. Count the number of layers.
     layers
  1. Count the number of cubes along the:
    1. Length (l)  cubes
    2. Width (w)  cubes
  2. By counting, find the volume of the cube in cm3.
     cm3
  3. Relate the number of 1 cm cubes along the length, width and height with
    1. total number of 1 cm cubes counted.
    2. measurement of each side.

Note

The number of cubes
​=
​length (l) × width (w) × height (h)

Volume
​=
​length (l) × width (w) × height (h)
​=
​Area × height

The number of cubes along each side represents the length of each side in centimetres.

Example 3

Find the volume of the cube shown.

Volume = length (l) × width (w) × height (h)
​= 5 cm × 5 cm × 5 cm
​= 25 cm2 × 5 cm
​= 125 cm3

Cube

Exercise D

1.  cm3

2.  cm3

3.  cm3

4.  cm3

5.  cm3

6.  cm3

Volume of cuboids using the formula

In groups of five:

  1. Use 1 cm cubes to make a cuboid as shown.
  2. Count the number of 1 cm cubes.
     cubes
  1. Count the number of 1 cm cubes along:
    1. The length (l)  cubes
    2. The width (w)  cubes
    3. The height (h)  cubes
  2. Relate the number of cubes along the length (l), width (w) and height (h) with the number of 1 cm cubes counted.
  3. Discuss and share your results with other groups.

Note

Volume of cuboid
​=
​length (l) × width (w) × height (h)

Volume, V = l × w × h

Cuboid

Example 4

Find the volume of the cuboid shown.

Volume = length (l) × width (w) × height (h)
​= l × w × h
​= 5 cm × 2 cm × 3 cm
​= 10 cm2 × 3 cm
​= 30 cm3

Exercise E

1.  cm3

2.  cm3

3.  cm3

4.  cm3

5.  cm3

6.  cm3

7.  cm3

8.  cm3