Q10 of 26 Page 183

The length of diameter of base of a hemispherical tomb is 42 dm. Let us write by calculating the cost of colouring the upper surface of the tomb at the rate of ` 35 per square metre.

Given:


Diameter of base = 42dm


Formula used:


1. Diameter of hemisphere = 2×Radius


Radius = 42/2 = 21dm = 2.1m


2. Surface area of hemisphere = 2×π×r2



⇒ Surface Area = 2×π×(2.1)2 = 27.72 m2


3. Cost of coloring = Surface Area × Cost per sq m


Cost of coloring = 27.72 × 35 = Rs.970.2.


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