How Do You Calculate the Perimeter of the Base of a Rectangular Prism?


To obtain the perimeter of a rectangular base, add all the sides using the formula P = 2l + 2w, where P is the perimeter, l is the length, and w is the width. You need ruler or a tape measure, a pen and a piece of paper. The process takes just a few minutes.

  1. Determine the dimensions of the base

    The base of a rectangular prism has four sides. The two lengths of the base are equal and the two widths are equal as well. Measure the sides using a ruler or a tape measure.

  2. Multiply the value of each dimension by 2

    Multiply the length by 2. Do the same with the width.

  3. Add the products

    Add the values obtained from the previous step. The sum is the perimeter of the base of a rectangular prism.