Volume of Rectangular Prisms — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. The formula for the volume of a rectangular prism is V = l × w × h.
The three dimensions of a rectangular prism are length (l), width (w), and height (h).
2. A small cube with side length 1 unit used to measure volume is called a unit cube.
A unit cube has side length 1. Volume is measured by counting how many unit cubes fit inside.
3. Volume is measured in cubic units such as cm³ or in³.
Cubic units reflect three dimensions. cm³ means centimeters × centimeters × centimeters.
4. A rectangular prism has three dimensions: length, width, and height.
Dimensions describe the size of a shape in each direction — length, width, and height for a 3D prism.
5. A rectangular prism is a 3D shape with six rectangular faces.
A rectangular prism (box shape) has 6 faces, all of which are rectangles.
6. A prism 10 cm × 5 cm × 2 cm has a volume of 100 cm³.
V = 10 × 5 × 2 = 100 cm³.
7. The volume of a cube with side length 4 m is 64 m³.
V = 4 × 4 × 4 = 64 m³.
8. If each layer has 8 unit cubes and there are 6 layers, the volume is 48 cubic units.
Total = cubes per layer × number of layers = 8 × 6 = 48 cubic units.
9. Doubling the height of a rectangular prism doubles its volume.
V = l × w × h. Doubling h gives V = l × w × 2h = 2(l × w × h), which is double the original volume.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
3 cm × 4 cm × 5 cm
→ 60 cm³
100 cm³
6 cm × 2 cm × 7 cm
→ 84 cm³
84 cm³
8 cm × 3 cm × 3 cm
→ 72 cm³
60 cm³
5 cm × 5 cm × 4 cm
→ 100 cm³
72 cm³
3×4×5=60(idx2); 6×2×7=84(idx1); 8×3×3=72(idx3); 5×5×4=100(idx0)