Year 7 Interactive Maths - Second Edition

Area

The number of squares needed to cover a surface gives a measure of the area of the surface.

For example, the area of the rectangle ABCD is calculated by counting the number of squares.  So, the area of the rectangle is 40 squares.

E.g.  The area of the triangle ABC is calculated by counting the number of squares.  So, the area of the triangle is approximately 28 squares.

The following are applications of area:

• To calculate the number of tiles to be ordered to tile a kitchen floor, the area of the kitchen floor must be taken into consideration.
• It is known that 5 litres of paint is needed to cover 50 square metres.  To calculate the amount of paint needed to paint a room, we need to take into consideration the area of the walls, ceiling and windows.
• To calculate the amount of glass required for a window, we need to know the area of the window.

Finding the Area of a Plane Figure

Area is the size of the region enclosed within a plane figure.  To the carpenter or carpet layer, who is concerned with the amount of material to be used, measurement of area is very important.  An approximate area of a surface can be found by counting the number of squares on a surface as illustrated above.

Key Terms

area, surface, approximate area, counting squares, square units, hectares