GED Math Practice Test Prep — Practice Exam & Study Guide

To find the perimeter of a square, you can use the formula for perimeter, which is the sum of the lengths of all four sides. Since all sides of a square are equal, the formula simplifies to multiplying the length of one side by 4.

In this case, the side length is given as 5 cm. Therefore, the perimeter can be calculated as follows:

Perimeter = 4 × side length = 4 × 5 cm = 20 cm.

This calculation shows why the correct answer is indeed 20 cm, as it correctly reflects the total distance around the square using the given side length. Understanding this formula is essential because it applies universally to all squares regardless of their size, reinforcing the concept that the perimeter is simply a function of the side length multiplied by four.