Question

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18. The length and breadth of a
?
rectangle is in the ratio 5:4. If its
perimeter is 90 m, then its area
will be:
INET & KAZ., 2006-07)
(a) 500 m2
b) 360 m2
(c) 540 m2
(d) 900 m2
2​

Answer 1

Answer:

$perimeter = 90m \\ length = 5x \\ breath = 4x \\ perimeter \: of \: rectangle \\ = 2(l + b) \\ = 90 = 2(5x + 4x) \\ = 90 = 2 \times 9x \\ = 18x = 90 \\ = x = \frac{90}{18} \\ = x = 5$

$length = 5x \\ = 5 \times 5 \\ = 25m \\ breadth = 4x \\ = 4 \times 5 \\ = 20m$

Answer 2

☞Given :-

The length and breadth of a rectangle are in the ratio 5:4 . It's perimeter is 90 m .

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☞To Find :-

The area of that rectangle.

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☞Solution:-

First,find the both sides of rectangle

And let the ratio 5:4 be 5x and 4x.

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➜Formula :-

Perimeter of rectangle = 2(length + breadth )

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Perimeter of rectangle= 2(length + breadth )

90 = 2 (5x + 4x)

90 = 2 × 9x

90 = 18x

$\frac{90}{18} = x$

x = 5.

➜Since,

Length = 5×5 = 25

Breadth = 4×5 = 20

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➜Formula,

Area of rectangle = length × breadth

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Area of the given rectangle = length × breadth

Area. = 25 × 20

= 500 m.

➜ Hence,

The area of the rectangle is 500 m sqr.

First option is correct .

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