Calculating Area - Cycle 3

To learn how, consult the concept sheet Converting Units for Measuring Length.

Example:

I choose to convert 50 mm into cm to have a single unit of measurement.

Follow these steps to calculate the area of a figure.

1. I verify that the measurements are given using the same unit. If not, I convert them.
2. I multiply the length by the width to obtain the area.

What is the area of the figure in square decimetres (dm²)?

I verify that the measurements are given using the same unit. If not, I convert them. To learn how, I can consult the concept sheet Converting Units of Measurement for Length. Since I need to find the area of the figure in dm², I will convert 10 m into dm.
I multiply the length by the width to obtain the area.	100 dm × 40 dm = 4 000 dm²

The figure has an area of 4 000 dm².

Follow these steps to calculate the area of a complex figure:

1. I verify if the measurements are given using the same unit. If not, I convert them.
2. I decompose the figure into squares or rectangles.
3. I calculate the area of each section by multiplying the length by the width.
4. I add the areas of each section to obtain the total area.

What is the area of the figure in square meters (m²)?

I verify if the measurements are given using the same unit. If not, I convert them. Since I need to find the area of the figure in m², I will convert 20 dm to m.
I decompose the figure into squares or rectangles. I get 2 rectangles: A and B.
I calculate the area of each section by multiplying the length by the width. Figure A has a length of 8 m and a width of 2 m. Figure B has a length of 3 m and a width of 2 m.	A : 8 m × 2 m = 16 m² B : 3 m × 2 m = 6 m²
I add the area of all the sections to obtain the total area.	16 m² + 6 m² = 22 m²

The area of the figure is 22 m².