Geometry and measuresKey Stage 3

Perimeter of a polygon

Add all the outside edge lengths.

  • Perimeter is the distance around the outside of a shape.
  • Include every outside edge once.
  • Give the answer in length units, such as or .

Example 1

Find the perimeter of the rectangle.

Opposite sides of a rectangle are equal.

Example 2

Find the perimeter of the triangle.

Add the lengths of all three outside edges.

Your turn

Question 1

Find the perimeter of the rectangle.

Check answer
Opposite sides of a rectangle are equal.
Question 2

Find the perimeter of the triangle.

Check answer
Add the lengths of all three outside edges.
Question 3

Find the perimeter of the rectangle.

Check answer
Opposite sides of a rectangle are equal.
Question 4

Find the perimeter of the triangle.

Check answer
Add the lengths of all three outside edges.
Question 5

Find the perimeter of the rectangle.

Check answer
Opposite sides of a rectangle are equal.
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