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Find the cost of polishing

Posted January 19th, 2008 by alpha
in

Find the cost of polishing a hemispherical bowl at the rate of Rs. 5/m^2.If the inner radius of the bowl is 7cm and thickness is 1/2 cm .

‹ Prove that this quadrilateral is a parallelogram Circle drawn on the side of an isosceles triangle ›

Comments

Answer

On February 2nd, 2008 Structure says:

You have to find out the surface.
Sphere surface=$ 4\pi R^2 $
Hemisphere surface $ 2\pi R^2 $
Total area=$ 2\pi R^2+2\pi r^2+\pi R^2-\pi r^2=3\pi R^2+\pi r^2= $ =$ \pi(3*0.075^2+0.07^2)m^2=\pi(3*0.005625+0.0049)m^2= $
$ \pi(0.016825+0.0049)m^2=\pi0.021725m^2=0.068251m^2 $
Cost of polishing=$ 0.068251m^2*5Rs/m^2 $
Please explain more about currency you use .

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