Curriculum › Math ›Grade 6

Grade 6 Math · Level 4, Coordinate Geometry & 3D Geometry

Volume of Rectangular Prisms

How the lesson starts: Volume of Rectangular Prisms

1. Gus's Sugar Cube Shop

   Welcome to Gus's Sugar Cube Shop! Gus packs tiny sugar cubes into boxes of every size. Customers always ask the same question: how many cubes fit inside? That amount of space is called volume. Let's help Gus!

2. Layer by layer

   Gus fills a box one layer at a time. The bottom layer is 4 long and 3 wide: 12 cubes. Then a second layer on top: 12 more. 2 layers of 12 make 24 cubes. The volume is 24 cubic units! That's why we multiply: the bottom layer times the number of layers.

3. The volume formula

   So V = l × w × h. A gift box is 5 cm by 4 cm by 3 cm. 5 × 4 = 20 cubes in a layer, and 20 × 3 = 60. Its volume is 60 cm³. Watch out: 5 + 4 + 3 = 12 adds the edges. That doesn't count the cubes inside!