Volume of prisms and cylinders

  • Volume is the amount of space occupied by a 3D object.
  • It is measured in cubic units (e.g., cm³, m³).

A prism is a 3D shape with two identical, parallel bases and rectangular sides.

Volume = Base Area × Height

  • Rectangular prism:

V = l × w × h

  • Triangular prism:

V = 1/2 × Base × Height × Prism Height

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
  • 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).
  • Measuring the capacity of tanks, pipes, and boxes.
  • Calculating the amount of material needed for construction.
  • Understanding storage space in packaging.

_______ 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?

______ 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?

_______ 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!