The number of sides and how those sides relate to one another defines a polygon's shape and type. A polygon, a closed two-dimensional shape constructed of multiple straight sides, can be either regular or irregular. The polygon's side lengths and interior angles are what separate it into the two classes -- the regular class has all sides equal in length and all interior angles identical in measurement, and the irregular class does not. A heptagon, the name given to a seven-sided polygon, has two different methods for finding its perimeter, one for regular heptagons and one for irregular ones.
Instructions
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1
Measure each side of an irregular heptagon with your ruler. For an example, the heptagon's seven sides measure 4.5, 4, 3.5, 6, 5, 2 and 4 inches.
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2
Add the seven lengths together to calculate the heptagon's perimeter -- the lengths of the seven sides in the example added together equals 29 inches.
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3
Multiply the length of one side by seven to calculate the perimeter of a regular heptagon. For example, a regular heptagon with one side measuring 6 inches has a perimeter of 42 inches, as 6 multiplied by 7 equals 42.