Page 108 - Maths Skill - 6

106 Maths

Example 4: Compare the area of a rectangle if its length and breadth are tripled?
Solution: Let l be the length and b be the breadth of a rectangle.

Further, let A be the area of the rectangle.
Then, A = l × b
Now, new length = 3l
New breadth = 3b

New area = 3l × 3b = 9(l × b) = 9A [ l × b = A]
Hence, the area of the new rectangle is 9 times the area of the actual rectangle.

Example 5: Find the area of a square whose side is 12.5 m.
Solution: Side of the square = 12.5 m
2
Area of the square = (side × side) = (12.5 × 12.5) m = 156.25 m 2

Exercise 7.2

2
1. Find the areas of the following irregular figures. Assume that each small square is 1 cm .
(i) (ii) (iii)

(iv) (v) (vi)

2. Fill in the blanks in respect of rectangles.
S. No. Length Breadth Area

(i) 9 cm 3.5 cm _________

(ii) 3 cm _________ 24 cm 2

(iii) _________ 7 cm 3.5 cm 2

3. Fill in the blanks in respect of rectangles.
S. No. Length Breadth Area Perimeter

(i) 4 cm 3 cm _________ _________

(ii) _________ 12 cm 240 cm 2 _________

(iii) 5 cm 8.5 cm _________ _________