Area of a rectangle

In your book, Maths Mela (Chapter 11), Preetha and Adrit's grandmother is making another patchwork of square patches. How many patches will she need? Preetha says, 'We don't need to count them all. There are 6 rows of 4 patches each. That is 6 × 4 = 24 patches.'

This works for every rectangle. The patches make rows and columns, so we multiply instead of counting one by one. The longer side is called the length and the other side is the breadth. Area of a rectangle = Length × Breadth. If each patch is a 1 cm square, the patchwork is 6 cm by 4 cm, and its area is 6 cm × 4 cm = 24 square cm.

A square is a rectangle whose sides are all equal, so its length and breadth are the same. Area of a square = Length × Length. A square with sides of 5 cm has an area of 5 × 5 = 25 square cm.

The rule also works backwards. A rectangular garden has an area of 64 square m and a length of 16 m. Length × Breadth = 64, so 16 × Breadth = 64. Since 16 × 4 = 64, the breadth is 4 m. And for big shapes it saves a lot of counting: a field 42 m long and 34 m wide has an area of 42 × 34 = 1,428 square m.