A dome of a building is in the form of a hemisphere. From inside, it was white-washed at the cost of 498.96. If the cost of white-washing is 2.00 per square metre, find (i) the inside surface area of the dome and (ii) volume of the air inside the dome.<p></p>

Given:Cost of white washing dome=498.96
Cost of white washing 1m² area=Rs.2
(i) CSA=498.96/2=249.48m²
(ii) Let ratio=r, CSA=249.48cm²
⇒249.48=2×22/7×r²
4πr²
⇒r²=249.48×7/44=39.7m²
⇒r=6.3m
Volume of air inside dome=Vol of hemispherical dome=2/3πr³=2/3×22/7×6.3×6.3=523.9m³

Eduprobe

Question:

A dome of a building is in the form of a hemisphere. From inside, it was white-washed at the cost of 498.96. If the cost of white-washing is 2.00 per square metre, find (i) the inside surface area of the dome and (ii) volume of the air inside the dome.

Solution: