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Mathematics

The length of a rectangular verandah is 3 m more than its breadth. The numerical value of its area is equal to the numerical value of its perimeter.

(i) Taking x as the breadth of the verandah, write an equation in x that represents the above statement.

(ii) Solve the equation obtained in (i) above and hence find the dimensions of the verandah.

Mensuration

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Answer

(i) Given:

Breadth of the verandah = x

Length of the verandah = x + 3

It is also given that the numerical value of the area is equal to the numerical value of the perimeter.

⇒ l x b = 2(l + b)

⇒ x(x + 3) = 2(x + x + 3)

⇒ x2 + 3x = 2(2x + 3)

⇒ x2 + 3x = 4x + 6

⇒ x2 + 3x - 4x - 6 = 0

⇒ x2 - x - 6 = 0

Hence, the equation is x2 - x - 6.

(ii) From (i),

⇒ x2 - x - 6 = 0

⇒ x2 - 3x + 2x - 6 = 0

⇒ x(x - 3) + 2(x - 3) = 0

⇒ (x - 3)(x + 2) = 0

⇒ x = 3 or - 2

Since breadth cannot be negative, x = 3 m.

Length = x + 3 = 3 + 3 m = 6 m

Hence, length = 6 m and breadth = 3 m.

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