Khan Academy
Volume of Rectangular Prisms
Length × width × height for box-shaped objects.
Watch on YouTubeSame length × width × height — even when the edges are fractions.
Read this first — it covers the idea in plain language with a worked example.
Volume of a rectangular prism is always length × width × height. When edges are mixed numbers, turn each into an improper fraction (or a decimal) first, then multiply.
Find the volume of a box that is 1½ ft × 2 ft × 4 ft.
Tip
Label every edge on your sketch before you multiply so you don't mix up the dimensions.
Watch the main video, then check the second take if you want another explanation.
Length × width × height for box-shaped objects.
Watch on YouTubeTry a worksheet or work through some problems before the quiz.
End-of-year mixed practice across area, surface area, and volume.
A couple of questions to make sure this topic stuck. Retake as many times as you want.
Volume with Fractions
A box has dimensions 2 ft × 3 ft × 5 ft. What is its volume?