Question

On increasing the diameter of circle by 40%, its area will be increased by

Answer 1

Step-by-step explanation:

Let the radius be r cm

∴area=πr

2

cm

2

New radius Newradius=r+40%orr

=r+

100

40

r=r+

5

2

r=

5

7

r

New area Newarea=π(

5

7

r)

2

=π

25

49

r

2

∴ Increase in area =

25

49

πr

2

−πr

2

=(

25

49−25

)πr

2

25

24

πr

2

∴ Percentage of increase in area

=

πr

2

25

24

πr

2

×100

=

25

24

×100=96%

Answer 2

Answer:

20%

i think this is the right answer