Measurement
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Comparisons using area

Lesson

What is area?

Area is the space taken up by a two dimensional (2D) shape. We can work out the area of a shape by seeing how many squares fit inside it.

 

Comparing Area

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

 

 

Square units

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 Video 1, we'll compare some shapes using a $1$1 cm unit square.

 

Different units of measurement

In Video 2, we look 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.

 

Everything's different!

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. By thinking about how  $1$1 cm2 compares to $1$1 mm2 and $1$1 m2, we can work out which might have the largest, or smallest area.

Remember!

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

Worked examples

Question 1

Look at the two shapes laid on the grid.

  1. Fill in the gaps below.

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

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

  2. Which is the smallest shape?

    Shape B

    A

    Shape A

    B

    Shape B

    A

    Shape A

    B

Question 2

Order the three shapes from largest to smallest area.

  1. Largest area: Shape $\editable{}$

    Second largest area: Shape $\editable{}$

    Smallest area: Shape $\editable{}$

Question 3

Here are two overlapping shapes on a grid of $1$1 mm squares.

  1. Which is the smallest shape?

    Shape B

    A

    Shape A

    B

    Shape B

    A

    Shape A

    B

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