Question

if length and breadth of rectangle are increased in ratio 3:4 and 4:5 resp. what is the ratio of old area to the new one?

Answer 1

Let the first rectangle be ABCD with ratio 3:4 and let the second rectangle be PQRS with ratio 4:5.
ar (□ABCD)=l×b
=3x ×4x=12x.
ar (□PQRS)=l×b
=4x ×5x=20x.
ar (□ABCD)/ar (□PQRS)=12x/20x
=3:5 is the ratio of the old area of rectangle to the area of new rectangle.

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