Question

the outer and inner diameter of hemispherical bowl is 17 cm and 15 cm respectively. find the cost of polishing it at cost of 25 paise per cm².​

Answer 1

Step-by-step explanation:

Curved surface rea of hemisphere.

For outer CAS

= 2pi R^2

=2 pi 17*17

=289*2*pi

=578pi

For inner CSA

=2pi r^2

=2*pi*15*15

=225*2*pi

=450pi

Now area of ring....

=2 pi(R^2 - r^2)

=2 pi (17^2 - 15^2)

=2 pi (289 - 225)

=2 pi 64

=138pi..

Total area to be polise

=578pi+450pi+138pi

=1166 pi

= 1166*22/7

=3664.6 cm^2

Cost of polishing

= 3664.4*24

=87950.4paisa

=87950.4/100

=rupee 879.5