Question

If all sides of a rectangle is elongated by 30%, what is the percentage change in area?​

Answer 1

Solution :

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Let us assume that the length and breadth of a rectangle are x metres and y metres respectively.

Area of the rectangle :

> [ Length × Breadth ]

> xy m² .

Now , all the sides are increased by 30%

The new Length becomes >

> 130% of x cm

> 13/10 x

The new breadth :

> 13/10 y

New Area :

> 169/100 xy .

Increase in area :

> [ 169/100 ] xy - xy

> 69/100 xy

Percentage change in area :

> 69/100 xy × xy × 100%

> 69%.

This is the required answer .

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