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Generalising for other Congruent Parts of Rectangles

Let us take a rectangle ABCD of length 6 cm and breadth 4 cm A 2 cm E 4 cm B

and divide into two parts as shown in the adjacent fig. Take
a point E at a distance of 2 cm from point A and take another
4 cm
point F at a distance of 2 cm from point C and join them. Each
part thus obtained superposes other part.
D 4 cm F 2 cm C
Thus, we can say that both parts are congruent to each other.
1
The area of each congruent part = × Area of the rectangle
2
1
From the given figure, the area of each congruent part = × (6 cm × 4 cm) = 12 sq. cm
2

Think and Answer

Each of the following rectangles of length 6 cm and breadth 4 cm is composed of congruent polygons. Find
the area of each polygon.

Practice Time 13A

1. Find the perimeter and area of the following rectangles:
(a) Length = 17 cm, breadth = 9 cm (b) Length = 9.5 m, breadth = 6.5 m

(c) Length = 12.7 cm, breadth = 90 mm (d) Length = 1.5 km, breadth = 610 m.
2. Find the perimeter and area of the following squares, the length of whose sides are:
(a) 9.5 cm (b) 25 cm (c) 11.5 mm (d) 0.06 m

3. Find the area of shaded part of the given figure.
5 cm

1 cm

3 cm

3 cm

1 cm
5 cm

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