Q8 of 48 Page 261

The cost of painting the surface of sphere is Rs. 1526 at the rate of Rs. 6 per m2. Find the radius of sphere.

Given.


Cost of painting the surface of sphere is Rs. 1526


Rate of Rs. 6 per m2


Formula used/Theory.


TSA of sphere = 4πr2


Let radius of sphere is r


Then area of sphere is 4πr2 m2


Rate of painting = Rs. 6 per m2


Cost of painting of sphere =


4πr2 m2 × Rs. 6 per m2


Rs. 24πr2


Rs. 24πr2 = Rs. 1526


24 × × r2 = 1526


r2 = = 20.23


r = √20.23 = 4.49 m


= 4.5 m


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