Q. 94.5( 243 Votes )
A wooden article was made by scooping out a hemisphere from each end of a solid cylinder, as shown in Fig. 13.11. If the height of the cylinder is 10 cm, and its base is of radius 3.5 cm, find the total surface area of the article.
Answer :
Given:
Radius (r) of cylindrical part = 3.5 cm
Radius (r) of hemispherical part = 3.5 cm
Height of cylindrical part (h) = 10 cm
Surface area of article = CSA of cylindrical part + 2 × CSA of hemispherical part
= 2 πrh + 2 × 2 πr2
= (2 π × 3.5 × 10) + (2 × 2 π × 3.5 × 3.5)
= 70 π + 49 π
= 119 π
= 17 × 22
= 374 cm2
Hence, the total surface of the article = 374 cm2
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