Measurement · Grade 3

Rectangle Perimeter Worksheets

Perimeter measures the distance around a shape. Follow the boundary once and include every side.

6 problemsAnswer key includedFree printableA4 & US Letter

Follow all four sides

A rectangle is 6 units long and 3 units high. Opposite sides have equal lengths, so the four sides measure 6, 3, 6, and 3 units.

6 + 3 + 6 + 3 = 18 units

You can also add the two different lengths and double: 2 × (6 + 3) = 18.

Two labels describe four sides

The diagrams label one horizontal length and the height. Use the same horizontal length for the opposite side, and the same height for the other upright side. Trace the border with a finger and say each length once.

If a child answers 9 for the example: ask which sides 6 + 3 includes. Those two sides cover only part of the boundary. Continue around the remaining two sides before adding.

Read the labels instead of measuring the drawing

These diagrams are not drawn to scale. A longer-looking edge is not evidence of a larger labeled length. Do not use a ruler to find the answer. If the two labeled lengths are equal, all four sides have that length even if the sketch looks stretched.

Keep perimeter separate from area

For a rectangle with sides 5 and 3, the perimeter is 5 + 3 + 5 + 3 = 16 units. Its area is 5 × 3 = 15 square units. Perimeter follows the boundary; area measures the surface inside. In this worksheet, write a boundary length in units.

Check by grouping equal sides

After adding all four sides, add the two long sides together and the two short sides together. The result should agree. For sides 8 and 2, both 8 + 2 + 8 + 2 and 16 + 4 give 20 units.

About this practice

Each set has six distinct pairs of side lengths from 2 through 9 units. The original diagrams and numerical answers are preserved. The answer key gives the total perimeter. Use the space below each picture to record a sum that shows all four sides.

This practice covers rectangles with known side lengths. Missing-side problems, irregular polygons, area grids, and comparing shapes with the same perimeter are separate activities.

Make a practice set

Choose what to print. Selecting both shows the answer key on screen and prints the questions followed by the answers.

Print materials

After the practice

Ask the child to trace one rectangle and explain how two labels determine all four sides. Check that the written sum includes each side exactly once.

More about measurement · Grade 3 worksheets

Grade 3 selected skill connection: 3.MD.D.8. See the Common Core grade guidance. This worksheet does not cover every requirement in the standard.