Concept of perimeter (3rd grade math)

Perimeter is essentially the "walk-around" measure, or (from the Greek peri-metros) "around-measure". We find the perimeter of rectangular shapes on a grid by counting the units. Lastly, we find the perimeter of two shapes by measuring their side lengths first and adding those. Remember always to add the correct unit of length to your answer. :)

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In the second part of the lesson, we find the perimeter of a square, a rectangular shape when some side lengths are not given, of a parallelogram, and of a regular pentagon. Just simple and easy practice problems for finding the perimeter of shapes.

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See also

Area and perimeter problems — rectangular shapes — video lesson

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