Question

12. The sides of a rectangle are 20 cm and 15 an. If each side of the rectangle is increased by 20%, find the
percentage increase in the area,​

Answer 1

here is your answer

L= 20cm

B= 15cm

area= L×B

=20×15cm2

= 300cm2

new length = 20+20% of 20

= 20+20/100×20

= 24cm

new breadth = 15+20% of 15

= 15+20/100×15

= 18cm

new area = 24×18 cm2

= 432cm2

% of area increased = (432-300)/300×100%

= 132/2

= 44

so the answer is 44%

hope this will help you

have a great day

Answer 2

Given :

Length of rectangle = 20 cm

Breadth of rectangle = 15 cm

To find :

The percent increase in area if sides are increased by 20%

Solution :

Area of original triangle = length × breadth

= 20 × 15

= 300 cm²

Now, increasing the sides by 20%

length = (20/100 × 20) + 20 = 4 + 20 = 24

breadth = (20/100 × 15) + 15 = 3 + 15 = 18

New area = 24 × 18 = 432

Percentage of area increased,

(change in area)/original area × 100

(432 - 300)/300 × 100

132/3

44%

Therefore,

44% is increased.