113
Volume of a cuboid
Textbook: Part 4, lesson 113, pp. 10–12
GoalFind the volume of a cuboid with the formula V = a × b × c.
New words
volume · hajmcuboid · kuboidheight · balandlikcube · kub
Explanation
The volume of a cuboid tells how many unit cubes fit inside it. V = a × b × c, where a is the length, b the width and c the height. If the area of the base S and the height h are known, V = S × h. Volume is measured in cm³, dm³, m³, and 1 dm³ = 1 l.
Worked examples
A cuboid measures 5 cm, 4 cm and 3 cm. V = 5 × 4 × 3 = 60 cm³.
A box has a base of 48 dm² and a height of 5 dm. V = 48 × 5 = 240 dm³, so it holds 240 l of water.
Class activity
“Building with cubes”: children build a 3 × 2 × 2 cuboid from unit cubes, count layer by layer to find its volume and compare with the formula.
Practice
1
A cuboid is 8 cm long, 5 cm wide and 2 cm high. What is its volume in cm³?
80
2
An aquarium is 60 cm long, 30 cm wide and 40 cm high. What is its volume in cm³?
72000
3
The edge of a cube is 6 dm. What is its volume in dm³?
216
4
The bottom of a small tank measures 6 dm × 4 dm and the water is 3 dm deep. How many litres of water are in it? (1 dm³ = 1 l)
72