Question

the area of a small rectangular plot in 84m^2.if the difference between its length and the breadth is 5m, find its perimeter.

Answer 1

Answer:

Step-by-step explanation:

Let length of rectangular field = l

And

Breadth of rectangular field = b

Given : The difference between the length and breadth is 5 m , So

l - b = 5

l = b + 5 ----- ( 1 )

And area of rectangular plot = 84 m2 , So

l b = 84 , Substitute value from equation 1 and get

( b + 5 ) b = 84

b2 + 5 b = 84

b2 + 5 b - 84 = 0

b2 + 12 b - 7 b - 84 = 0

b ( b + 12 ) - 7 ( b + 12 ) = 0

( b - 7 ) (b + 12 ) = 0

So,

b = 7 and - 12

But breadth can't be negative so we neglect b = - 12

Then we get

b = 7 , Substitute that value in equation 1 and get

l - 7 = 5

l = 12

We know perimeter of rectangle = 2 (Length + Breadth )

So,

perimeter of rectangular plot = 2 ( 12 + 7 ) = 2 ( 19 ) = 38 m ( Ans )

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