Sometimes we may only want an idea of the area of something, without needing an exact measurement. In such a case there are some techniques we can use to estimate area:

Using a mental image of a common objects of size $1$1 mm², $1$1 cm², $1$1 m² and/or $1$1 km², try to picture how many it would take to cover the object.
For shapes that are rectangular (or close to rectangular), we can estimate the length and width of the object and then multiply: $\text{Area}=\text{length}\times\text{width}$Area=length×width.
If a picture of the item is available, you could draw a scale grid over it and estimate by counting the number of squares needed to cover the item.

Practice questions

Question 1

Estimate the area of the artwork above the sofa if the sofa is $1.9$1.9m in length.

$1.7$1.7 m²
A
$0.01$0.01 m²
B
$5$5 m²
C
$0.5$0.5 m²
D

Question 2

Estimate the area of the curved shape below if each square on the grid has an area of $3$3 $mm$ ².

$111$111 $mm$ ²
A
$72$72 $mm$ ²
B
$26$26 $mm$ ²
C
$48$48 $mm$ ²
D

Question 3

Which of these objects do you think would have an area of about $1$1m²?

$goal area on a football field$
A
$lid of a shoe box$
B
$coffee table$
C
$baking tray$
D

Outcomes

ACMEM021

use metric units of area, their abbreviations, conversions between them, and appropriate choices of units

ACMEM022

estimate the areas of different shapes

4.035 Estimating area

Estimating area