The perimeter of the rectangle is 120 cm and the ratio of the length to the breadth of the rectangle is 7:8. Area of square is 4 cm2 more than the area of rectangle. Find the side of square?
- AOption (a)
30
- BOption (b)
44
- COption (c)
32
- DOption (d)
36
- EOption (e)
40
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Correct answer
30
Why this answer is correct
Given:
Perimeter of the rectangle = 120 cm
Ratio of length to breadth = 7 : 8
Area of the square is 4 cm² more than the area of the rectangle.
Formula used:
Perimeter of rectangle = 2 × (Length + Breadth)
Area of rectangle = Length × Breadth
Area of square = Side²
Calculations:
Let the length = 7x and the breadth = 8x (from the ratio 7:8).
Perimeter = 2 × (Length + Breadth) = 2 × (7x + 8x) = 120
⇒ 2 × 15x = 120
⇒ 30x = 120
⇒ x = 4
Length = 7x = 7 × 4 = 28 cm
Breadth = 8x = 8 × 4 = 32 cm
Area of rectangle = Length × Breadth = 28 × 32 = 896 cm²
Let the side of the square be 's'.
Area of square = s²
We are given that the area of the square is 4 cm² more than the area of the rectangle:
s² = 896 + 4
s² = 900
⇒ s = √900
⇒ s = 30 cm
∴ The side of the square is 30 cm.