Which expression gives the volume of a rectangular prism?

• A. lwh
• B. Bh
• C. l + w + h
• D. B h / 2

Answer: (A)

Volume is the amount of space inside a 3D object. For a rectangular prism, think of the base as a rectangle with area l times w, and the height h as how tall the prism is. The total space inside comes from stacking layers of that base area up to height h, so you multiply: base area (l × w) by the height (h). That gives l × w × h as the volume.

The other expressions don’t measure 3D space in the same way. Base times height (Bh) only covers two dimensions and gives a 2D area rather than a 3D volume. Adding the dimensions (l + w + h) yields a linear sum, not a measure of space inside. And the form Bh/2 matches the area of a triangle, not the volume of a prism.