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Lesson 1 of 8 · Grades 3 to 6

Practice: Perimeter of polygons

Ten perimeter questions: rectangles, squares, triangles and polygons, plus two questions where the perimeter is known and one side is missing.

How to use this page

This page gives you ten more questions on the same idea as the lesson "Perimeter of polygons". Work through them at your own speed. Write your answer down or say it out loud before you open the answer box, so you give yourself a real chance to think.

If a question feels hard, go back to the lesson and look at the worked example again. Getting a question wrong is useful; it shows you the part that needs one more look.

Practice questions

Answer all ten questions in your notebook or in your head. Then open each answer to check your work.

  1. A square has a side of 9 m. What is its perimeter?

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    36 m. 4 × 9 = 36 m.

  2. A rectangle is 11 cm long and 6 cm wide. What is its perimeter?

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    34 cm. 2 × (11 + 6) = 2 × 17 = 34 cm.

  3. A triangle has sides of 4 cm, 9 cm and 12 cm. What is its perimeter?

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    25 cm. 4 + 9 + 12 = 25 cm.

  4. A rectangle has a perimeter of 30 m and a length of 10 m. How wide is it?

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    5 m. The two long sides use 20 m, so 30 - 20 = 10 m is shared by the two widths, and 10 ÷ 2 = 5 m.

  5. A square has a perimeter of 28 cm. How long is one side?

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    7 cm. 28 ÷ 4 = 7 cm.

  6. A pentagon has sides of 3 cm, 5 cm, 5 cm, 6 cm and 7 cm. What is its perimeter?

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    26 cm. 3 + 5 + 5 + 6 + 7 = 26 cm.

  7. A rectangle is 15 m long and 7 m wide. What is its perimeter?

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    44 m. 2 × (15 + 7) = 2 × 22 = 44 m.

  8. A path around a square pond is 40 m long. How long is one side of the pond?

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    10 m. 40 ÷ 4 = 10 m.

  9. A triangle has a perimeter of 18 cm. Two sides are 5 cm and 6 cm. How long is the third side?

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    7 cm. 18 - 5 - 6 = 7 cm.

  10. A rectangle is 8 cm long and 3 cm wide. A second rectangle is 7 cm long and 5 cm wide. Which has the bigger perimeter?

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    The second rectangle. Its perimeter is 2 × (7 + 5) = 24 cm, and the first is 2 × (8 + 3) = 22 cm.