The perimeter is the distance around the outside of the square, and not the area, which is the space inside of the square. Knowing the perimeter is useful in a number of disciplines, including construction. Fortunately, finding the perimeter of a square is a straightforward operation that can be achieved in a few short steps.
Make sure the shape is a square. All four sides on a square are exactly the same size, and all four angles are right angles, or 90 degrees.
Find the length of any one side of the square; it doesn't matter which side, because they are all the same size. You can use a ruler to do this, but make sure to keep track of the units you used, such as inches or centimeters.
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Take the measurement of the side and multiply it by 4. You can use a calculator to do this. Alternatively, take the side length and add it to itself 3 times. Either operation will yield the perimeter. For example, if you've measured the side of the square to be 18 inches:
18 * 4 = 72; or
18 + 18 + 18 + 18 = 36 + 36 = 72
The perimeter is therefore 72 inches.