L2 · Area of Rectangles in cm2, m2 and km2

Learning goal

“I can find the area of a rectangle by multiplying its length by its width, state the area in square centimetres, square metres, or square kilometres, and explain how the units relate: 1 m2 = 10 000 cm2 and 1 km2 = 1 000 000 m2.”

Area — the amount of surface a shape covers, counted in unit squares. Area answers "how much covering?" - perimeter answers "how far around?"

Square centimetre (cm2) — the area of a square 1 cm by 1 cm - about the size of a fingernail or a postage stamp.

Square metre (m2) — the area of a square 1 m by 1 m - about the size of a large beach towel spread flat.

Square kilometre (km2) — the area of a square 1 km by 1 km - about the size of a very large park, or 100 soccer fields side by side.

Worked example

A rectangular mat is 9 cm long and 4 cm wide. Step 1: Picture the covering: unit squares in rows. Each row holds 9 squares (the length), and there are 4 rows (the width). Step 2: Counting all of them is 9 x 4. A = length x width = 9 x 4 = 36. Step 3: State the unit: the squares are centimetre squares, so A = 36 cm2. Say it plainly: multiplication replaces the counting because the squares form a perfect array - rows x squares per row. The answer ALWAYS wears a square unit.

Check yourself — explain it

In A = length x width, the two numbers being multiplied are...

Paired problem — example still visible

A rectangle is 11 m by 5 m -> A = 11 x 5 = 55 m2

Faded completion — last step is yours

"A rectangle is 8 cm by 7 cm: A = 8 x ___ = ___ cm2" -> 7; 56 cm2

Ready to practise?

10 scored questions with a 3-rung hint ladder. Mastery needs 8/10 plus both gate questions.

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