Question

The length of a rectangle is increased
by 30%. and breadth decreased by 20%.
The percentage change in area of rectangle.​

Answer 1

Answer:

there is an increase of 4% in area of rectangle

Step-by-step explanation:

let original length be l

let original breadth be b

new length is l+30% of l= l+0.3l=1.3l

new breadth is b-20% of b=b-0.2b=0.8b

original area = l*b

new area = 1.3l*0.8b=1.04lb

change in area = 1.04 lb-lb=0.04 lb

percentage change in area = {(0.04*lb)/lb}*100%  = 0.04*100% = 4%

Answer 2

Answer:

★ Percentage Change = 4 % ★

Step-by-step explanation:

Given:

• Length of rectangle is increased by 30%
• Breadth of rectangle is decreased by 20%

To Find:

• Total percentage change in area.

Solution: Let the Length of rectangle be 10 cm and Breadth be 10 cm.

∴ Area of rectangle = (Length x Breadth)

$\small\implies{\sf }$ Area of rectangle = 10 x 10

$\small\implies{\sf }$ Area of rectangle = 100 cm²

A/q

† Length is increased by 30 % †

• New Length = 10 + 30/100 of 10

$\small\implies{\sf }$ New Length = 10 + 30/10 [ Take LCM ]

$\small\implies{\sf }$ 100 + 30/10

$\small\implies{\sf }$ 130/10 = 13 Cm

† Breadth is decreased by 20 % †

• New Breadth = 10 – 20/100 of 10

$\small\implies{\sf }$ New Breadth = 10 – 20/10 [ Take LCM ]

$\small\implies{\sf }$ 100 – 20/10

$\small\implies{\sf }$ 80/10 = 8 Cm

★ Therefore, New area of Rectangle = New(Length x Breadth) ★

$\small\implies{\sf }$ New area = (13 x 8) cm²

$\small\implies{\sf }$ 104 cm²

∴ Percentage increase in area = (New area/Original area) x 100

$\small\implies{\sf }$ Increase percent = ( 104/100 ) x 100

$\small\implies{\sf }$ Increase percent = 104%

Hence, It is clear that there is an increase of 4% in area. [ 104 – 100 ]