Question

The length and breath of a rectangle incress 20%and its with his decreased by 20%how much percent will its area change​

Answer 1

Answer:

decrease by 8 %

Step-by-step explanation:

Let 'I' be the length lncrease = 20%

New length = 120100l=65l

Let b be the width. Decrease = 20%

New width = 80100b=45b

Original area = lb

New area = 65l×45b=2425lb

Change in area = lb−2425lb=125lb

Percentage in decrease = 100×125= 4%

Answer 2

Given :

• The length and breath of a rectangle increased 20% and its with his decreased by 20%.

To find :

• It's area change =?

Formula Used :

• Area of Rectangle = length x breadth

Step-by-step explanation :

It is Given that,

Length is increased by 20%.

So, 100 + 20 × l = 120 × l

•°• New length = 120 × l/100 = 1.2 × l

Now,

Breadth is decreased by 20 %.

So, 100 - 20 × b = 80 × b

•°• New breadth = 80 × b/100 = 0.8 × b

Now, We have to find the new area,

As We know that,

Area of Rectangle = length x breadth

Substituting the values in the above formula, we get,

= 1.2l × 0.8b

= 0.96lb.

Therefore, New area = 0.96lb.

Now,

Decreased in Area,

= Original area - New area / Original area

Substituting the values, we get,

= lb - 0.96lb/lb

= 0.04

= 4%.

Therefore, It's area change = 4%.