Area of the rectangle or square as the product of length and width
Rectangle
In pairs:
- Draw the rectangle shown.
- Join the given points to form unit squares.
- Count the number of square units.
square units - Count the number of rows and the number of columns.
rows and columns - Find the area of the rectangle by multiplying number of columns with number of rows.
cm2 - Discuss your results and share with other groups.
Note
- Area = Number of columns × Number of rows
= 6 × 4 square centimetres = 24 square centimetres
= 24 cm2
The number of columns form the length.
The number of rows form the width.
Area, A = Length (l) × Width (w) - In a square, number of columns = number of rows.
In a square of side 5 cm;
Area, A = 5 × 5 = 25 cm2.
Example 4
- Find the area of the rectangle with length 8 cm and width 6 cm.
Area of rectangle
= length × width
= 8 cm × 6 cm
= 48 cm2
- Find the area of a square of side 11 cm.
Area of a square
= length × width
= 11 cm × 11 cm
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Example 5
The area of a rectangle is 24 cm2. The length of the rectangle is 8 cm. What is the width of the rectangle?
Area of rectangle
= length × width
24 cm2 = 8 cm × width
Width = 24 cm2 ÷ 8 cm
Width of the rectangle is 3 cm.
Exercise F
a) cm2
b) cm2
c) cm2
d) cm2
a) cm2
b) cm2
c) cm2
d) cm2