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How do you solve problems?
LEARNING
STANDARDS
4
Solve problems involving
2
Given the area of a square garden is 500 m , find the perimeter perimeter and area of
of the garden. triangles, rectangles,
squares, parallelograms,
kites, trapeziums and
Let the length of the side of the garden = x m the combinations of
2
Then, x = 500 Area of the square is 500 m . these shapes.
2

Thus, x = 500
= 22.36 2 decimal places
Hence, the perimeter of the garden = 22.36 × 4
= 89. 44 m
5 T S R
The diagram shows a triangle PQS inscribed in a rectangle
PQRT. The perimeter of the rectangle is 42 cm and the length
of the rectangle is twice its width. Find the area of triangle PQS.
P Q

Let the length of the rectangle = y cm and the width of the rectangle = x cm
Perimeter = 42 cm
Thus, 2x + 2y = 42 …… 1
y = 2x …… 2 The length is twice its width. Perimeter of the
rectangle PQRT
Substitute 2 into 1, 2x + 2(2x) = 42 = 2(7) + 2(14)
6x = 42 = 14 + 28
42 = 42 cm
x =
6
= 7 CHAPTER
y = 2(7)
= 14 10
1
Hence, the area of triangle PQS = × 14 × 7
2
= 49 cm 2

Self Practice 10.3b

1. Given the perimeter of the square floor of a hall is 82 m, find the area of the floor of
the hall.
2. The length of a rectangle is 5 cm more than its width. If the perimeter of the rectangle
is 40 cm, find the area of the rectangle.
3. In the diagram, PQTU is a parallelogram with a U T 3 cm S
2
perimeter of 24 cm and an area of 28 cm . Given that 5 cm
UTS and PQR are straight lines, find the area of the
whole diagram. P Q R

241
Perimeter and Area

10 TB Math F1.indd 241 11/10/16 12:19 PM