Question

The length and breadth of a rectangle is twiced then by how much percent its area will increased?

Answer 1

let length of a rectangle =l
let breathe of a triangle = b
area of a rectangle = l× b

if l= 2l
b= 2b.
then area become

area of rectangle = 4lb
area increase. 4 time

Answer 2

$\underline \bold {Solution:-}$

Let the length of the rectangle be x and the breadth y.

Old area of rectangle = length × breadth

= x × y

= xy sq. units

When the length and breadth are twiced.

New length = 2x

New breadth = 2y

New area = New length × new breadth

= 2x × 2y

= 4xy sq. units

Area increased = New area - old area

Area increased = 4xy - xy

Area increased = xy(4 - 1)

Area increased = 3xy

Percent of area increased

$= \frac{area \: increased}{old \: area} \times 100 \\ \\ = \frac{3xy}{xy} \times 100 \\ \\ = 300\%$

So, the area increased by 300%.