8. Measurement

Lesson

We can work out the area of a shape by seeing how many squares fit inside it. Try this question.

Find the area of the shape by counting the number of grid squares it covers.

Each grid square represents $1$1 square unit.

When we compared length, we looked at which object was shorter, or longer than the other. We used number lines or lines to help us do this. We can do a similar thing with area, but instead of lines, we use squares.

Line | Square |
---|---|

When we compare area, we can use a square unit to do this. So if we are working with centimetres, we use a square measuring $1$1 cm x $1$1 cm. What would our square unit measure if we were using millimetres or metres?

In this video, we'll compare some shapes using a $1$1 cm unit square.

Look at the two shapes laid on the grid.

Fill in the gaps below.

The area of Shape A is $\editable{}$ square units.

The area of Shape B is $\editable{}$ square units.

Which is the smallest shape?

Shape B

AShape A

BShape B

AShape A

B

In this video we look at the area of objects in our everyday life, and how we might compare them. Which unit square should we use? What if we were to use a sheet of paper? Let's find out what happens when we do.

Caitlin's vegetable garden is $54$54m^{2}. Her flower garden is $27$27m^{2}.

Which garden is smaller?

Vegetable garden

AFlower garden

BVegetable garden

AFlower garden

B

If both our values (numbers) and units of measurement are different, we can use what we know about a unit square to help work out which shape might have the largest area.

Which of these is the larger area?

$40$40cm

^{2}A$40$40m

^{2}B$40$40cm

^{2}A$40$40m

^{2}B

Remember!

When comparing the area of objects, don't just compare the numbers. Remember to compare the units of measurement as well.

Compare objects using familiar metric units of area and volume

Compare the areas of regular and irregular shapes by informal means