Volume of prisms and cylinders
key notes :
Understanding Volume
- Volume is the amount of space occupied by a 3D object.
- It is measured in cubic units (e.g., cm³, m³).
Volume of a Prism
A prism is a 3D shape with two identical, parallel bases and rectangular sides.
Formula:
Volume = Base Area × Height
Types of prisms:
- Rectangular prism:
V = l × w × h
- Triangular prism:
V = 1/2 × Base × Height × Prism Height
Volume of a Cylinder
A cylinder has circular bases and a curved surface.
Formula: V=πr2hV = \pi r^2 hV=πr2h where:
- r = radius of the base
- h = height of the cylinder
- π≈3.14 or 22/7
Key Concepts
- Base area: The area of the shape forming the base of the prism or cylinder.
- Height: The perpendicular distance between the bases.
- Units: Always use cubic units for volume (e.g., cm³, m³).
Real-Life Applications
- Measuring the capacity of tanks, pipes, and boxes.
- Calculating the amount of material needed for construction.
- Understanding storage space in packaging.
Learn with an example
What is the volume?

_______ cubic millimetres.
Each side of the cube is 8 millimetres long. Use the number 8 in the formula.
volume=side . side . side
=8 . 8 . 8
=512
The volume is 512 cubic millimetres.
What is the volume of this cylinder?
Use 𝜋 ≈ 3.14 and round your answer to the nearest hundredth.

______ cubic millimetres.
Find the radius and height of the cylinder.
radius=1/2 . diameter=1/2 . 2=1
height=2
Use these numbers in the volume formula. Use 3.14 for 𝜋.
volume=𝜋r2 h
≈ 3.14 . 1 . 1 . 2
≈6.28
The volume of the cylinder is about 6.28 cubic millimetres.
What is the volume of this cylinder?
Use 𝜋 ≈ 3.14 and round your answer to the nearest hundredth.

_______ cubic millimetres.
Find the radius and height of the cylinder.
radius=1/2 . diameter=1/2 . 2=1
height=2
Use these numbers in the volume formula. Use 3.14 for 𝜋.
volume=𝜋r2 h
≈ 3.14 . 1 . 1 . 2
≈6.28
The volume of the cylinder is about 6.28 cubic millimetres.
let’s practice!