FTCE Mathematics Grade 5-9 Practice Test 2026 - Free Practice Questions and Study Guide

To find the volume of a rectangular prism, you multiply the length, width, and height of the prism together. This formula captures the three-dimensional nature of the space within the prism. Each dimension—the length, width, and height—contributes to the total capacity of the prism to hold objects or substances.

In practical terms, you can visualize this by considering that the base of the prism is a rectangle formed by the length and the width. The height then extends this rectangle upward, stacking layers of this rectangular base on top of one another to fill the entire space. Therefore, the product of length, width, and height gives you the total volume expressed in cubic units.

The other options, while involving the dimensions of the prism, do not accurately reflect how volume is determined for a three-dimensional object. For instance, simply multiplying length and width would only give the area of the base. Adding the dimensions together, either in a linear format or by utilizing a factor of 2, fails to account for the depth needed to establish volume in three dimensions. Thus, the correct method is indeed volume = length × width × height.