If each side of a square is 5 units long, how many total units are there in the perimeter?

To find the total perimeter of a square, you need to add together the lengths of all four sides. A square has four equal sides. Thus, if each side measures 5 units, you can calculate the perimeter using the formula:

Perimeter = 4 × side length

Substituting the given side length into the formula:

Perimeter = 4 × 5 = 20 units.

This calculation confirms that the total perimeter of the square is indeed 20 units, making this answer correct. The other options do not match the calculated perimeter, as they result from either underestimating or overestimating the contributions of the square's sides.