Head office, Rana Pratap Bagh, Delhi011 2721 1512+91 97116 99511

Perimeter and area

Find the distance around a shape (perimeter) and the space inside it (area) for rectangles, squares and triangles.

Get the whole book: Maths for classes 3 to 5 (4 lessons, free to print)

Let us begin

The big idea

If you walk around a cricket ground, you cover its perimeter. If you cover the whole ground with grass, you cover its area. Let us measure both.

Perimeter is the total length of the boundary of a shape. To find it, add the lengths of all the sides. It is measured in cm or m.

For a rectangle, the perimeter is length + breadth + length + breadth, or 2 × (length + breadth). For a square with side s, it is 4 × s.

Area is the amount of flat space inside a shape. It is measured in square units such as square cm (sq cm) or square m (sq m).

For a rectangle, area = length × breadth. For a square, area = side × side. Count the unit squares to see why: 6 rows of 4 squares is 24 squares.

A rectangle 6 cm by 4 cmA rectangle drawn on a grid of unit squares. It is 6 squares long and 4 squares wide. Under the picture the perimeter is worked out as 20 cm and the area as 24 square cm. 6 cm 4 cm Perimeter = 6 + 4 + 6 + 4 = 20 cm Area = 6 × 4 = 24 sq cm
Each small square is 1 cm by 1 cm. Perimeter is the distance round; area is the number of squares inside.

Worked examples

See how it works

  1. Perimeter of a rectangle

    A rectangle is 8 cm long and 5 cm wide. Perimeter = 8 + 5 + 8 + 5 = 26 cm. Or 2 × (8 + 5) = 2 × 13 = 26 cm.

  2. Area of a rectangle

    The same rectangle has area 8 × 5 = 40 sq cm.

  3. A square

    A square has side 7 m. Perimeter = 4 × 7 = 28 m. Area = 7 × 7 = 49 sq m.

  4. A triangle and a fence

    A triangle has sides 5 cm, 6 cm and 7 cm. Perimeter = 5 + 6 + 7 = 18 cm. A rectangular park is 30 m by 20 m. Fence all round: 2 × (30 + 20) = 100 m.

Try it at home

Squares on a page

You will need

  • A squared notebook page (or paper with a grid drawn on it)
  • A pencil
  • A ruler

What to do

  1. Draw a rectangle that is 5 squares long and 3 squares wide.
  2. Count the squares inside. That is the area. 5 × 3 = 15.
  3. Count the edges of squares along the outside. That is the perimeter. 5 + 3 + 5 + 3 = 16.
  4. Draw two more rectangles and find their area and perimeter.
  5. Can two rectangles have the same area but different perimeters? Try 2 by 6 and 3 by 4.

Ask a grown-up: No special help is needed. An adult can check the counting and the multiplication.

Practice sheet

Check what you learned

Write your answers in a notebook, or print this sheet and write on it. When you finish, mark your work with the answer key.

Practice sheet: Perimeter and area (Classes 3-5, Maths)

  1. What does perimeter measure?
  2. A square has side 5 cm. What is its perimeter?
  3. A rectangle is 9 cm long and 4 cm wide. What is its perimeter?
  4. A rectangle is 6 cm long and 3 cm wide. What is its area?
  5. A square has side 8 cm. What is its area?
  6. A triangle has sides 7 cm, 8 cm and 9 cm. What is its perimeter?
  7. A garden is 12 m long and 8 m wide. How much fencing is needed to go all round it?
  8. What is the area of the same garden?
  9. A rectangle has area 36 sq cm and length 9 cm. What is its width?
  10. A square has perimeter 36 cm. What is the length of one side?

Answer key

Answers: Perimeter and area

Do the practice sheet first, then check here. If an answer is different from yours, read the lesson again and try once more.

  1. The distance all round the edge of a shape.
  2. 20 cm (4 × 5).
  3. 26 cm (2 × (9 + 4)).
  4. 18 sq cm (6 × 3).
  5. 64 sq cm (8 × 8).
  6. 24 cm (7 + 8 + 9).
  7. 40 m (2 × (12 + 8)).
  8. 96 sq m (12 × 8).
  9. 4 cm (36 ÷ 9).
  10. 9 cm (36 ÷ 4).

What next

Keep learning

Get the whole book

All 4 maths lessons for classes 3 to 5 on one page, with every practice sheet and answer key, ready to print.

Maths for classes 3 to 5

All 136 lessonsAll printable books

WhatsApp us