Perimeter: Add the Sides Worksheets for 3rd Grade
Find the perimeter of triangles, quadrilaterals and other polygons by adding the side lengths. 15 free printable worksheets, each with an answer key.
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Click a worksheet to open the PDF, or grab the matching answer key. Every sheet prints on one page.
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Perimeter: Add the Sides: what children learn
The perimeter of a polygon is the total distance around it, found by adding the lengths of all its sides. Every side is labelled, so the pictures are drawn to scale.
Perimeter: Add the Sides: worked example
A triangle has sides of 4, 5, and 6 units. What is the perimeter in units? 15
Add all three sides: 4 + 5 + 6 = 15. The perimeter is 15 units.
Perimeter: Add the Sides: a common mistake to watch for
Kids sometimes add only the sides they can see labelled next to each other and skip one side.
Perimeter: Add the Sides: how to help at home or in class
Draw an odd polygon on paper with a ruler, label every side in centimeters, and put a dot on one corner to mark the starting point. Your child walks a pencil around the outline, crossing off each side as it is added to the running total. Try a second shape with five sides. When no side is skipped and the sums are accurate, rectangles offer a shortcut.
What is on these Perimeter: Add the Sides worksheets
This set has 15 different worksheets for 3rd grade, with 9 questions on each and a matching answer key for every sheet. The instruction printed on each worksheet is: “Add the side lengths. Write the perimeter in units.”
Every answer on every sheet is checked by a separate program before the worksheet is published. How we check answers