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.
Area is measured in square units. The most frequently used units of area are mm2, cm2 and m2. Land areas are often given in
hectares (ha).
1 ha = 10 000 m2
Areas of the following figures are often required to solve real world
problems.
Area of a Square
Recall that:
A square with sides of
length s units has an area of A square units given by the
formula
Example 13
Find the area of a square flower bed of side 7.2 m.
Solution:
Note:
To find the area of a region enclosed within a plane figure, draw a
diagram and write an appropriate formula. Then substitute the given values
and use a calculator, if necessary, to obtain the required area.
Area of a Rectangle
Recall that:
A rectangle with length l units and
width w units has an area of A square units given by the
formula
Example 14
Find the area of a rectangular field 45 m long and 38 m wide.
Solution:
Area of a Triangle
Recall that:
A triangle with base b units and height h units has an area of A square units given by the formula
Example 15
Find the area of a triangle with base 19 cm and height 13 cm.