Measurement, area & perimeter
Introducing area
Area is the amount of space a shape covers. On squared paper you can find the area by counting the squares inside the shape.
What area means
Area is the amount of space that a shape covers. It is measured in square units. Area is different from perimeter. The perimeter is the distance around the edge, but the area is the space inside.
Counting squares
On squared paper, each little square is 1 square unit. To find the area, count the squares inside the shape. A shape that covers 4 squares has an area of 4 square units. Be careful to count the squares inside, not the ones outside.
Area of rectangles and squares
For a rectangle you can count the squares in a row, then count the rows. A rectangle 4 squares wide and 2 squares tall covers 4 × 2 = 8 squares. A square 3 by 3 covers 3 × 3 = 9 squares.
Worked examples
Counting squares to find area
- The shape sits on squared paper.
- Count the squares inside the shape: it covers 4 squares.
- Each square is 1 square unit.
Answer: The area is 4 square units.
Area of a rectangle
- The rectangle is 4 squares wide and 2 squares tall.
- Count the squares in one row: 4.
- There are 2 rows, so count 4 twice: 4 × 2.
Answer: The area is 8 square units.
Finding the side from the area
- A square has an area of 81 square units.
- A square has equal sides, so find the number that times itself makes 81.
- 9 × 9 = 81.
Answer: Each side is 9 units long.
Where you see this in real life
- Counting floor tiles to cover a room.
- Working out how much space a rug takes up.
- Finding how many squares a shape covers on grid paper.
Key words
- Area
- The amount of space a shape covers.
- Square unit
- One square on the grid, used to measure area.
- Perimeter
- The distance all the way around the edge of a shape.
- Estimate
- A sensible guess for the area before you count exactly.
- Half square
- Half of one grid square. Two half squares make one whole square.