Mathematics ACT Aspire Practice Test 2026 – Complete Study Resource

The surface area of a rectangular prism is calculated using the formula that takes into account the areas of all six rectangular faces of the prism. Each face corresponds to a pair of the prism's dimensions: length, width, and height.

The formula states that the surface area is equal to 2 times the sum of the areas of all three distinct pairs of faces. Specifically, it adds together the areas of the three different face types—width times height (for the two faces that have height and width), length times height (for the two faces that have height and length), and length times width (for the two faces that have length and width). The whole expression is then multiplied by 2 to account for the fact that there are two of each face type in the prism.

This comprehensive approach ensures all surfaces are included when calculating the total surface area, making the formula accurate for any rectangular prism.