Question

if the radius of circle is increased by 8% then percentage increase in its area​

Answer 1

Answer:-

the percentage increase in the area of the circle is 16.64 % when radius is increased by 8 %.

Solution:-

Let the radius = r cm

Therefore surface area of circle = π r²    ( ∵ area of circle is π r²  )

Now the radius is increased by = 8 %

Therefore,  new radius becomes

=> $r+r$ × 8 %

=> $r+\frac{8r}{100}$

=> $1.08r$

therefore area of new circle is given by

$\pi r^2=\pi (1.08r)^2=1.1664\pi r^2$

increased area = New area  - original area

                 = $1.1664 \pi r^2- \pi r^2= 0.1664 \pi r^2$

Now percentage of increased area is given by

$Increaae \ area \ percent = \frac{increase \ area}{original \ area}$ × $100$

  = $\frac{0.1664\pi r^2}{\pi r ^2}$  × $100$

=> 16.64 %

                                                               

may be this is helpful for you

 

Answer 2

Step-by-step explanation:

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