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A cubical block of side 7 cm is surmounted by a hemisphere. What is the greatest diameter the hemisphere can have? Find the surface area of the solid. [Use π = 227] - Mathematics

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प्रश्न

A cubical block of side 7 cm is surmounted by a hemisphere. What is the greatest diameter the hemisphere can have? Find the surface area of the solid. [Use `pi = 22/7`]

योग
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उत्तर

From the figure, it can be observed that the greatest diameter possible for such hemisphere is equal to the cube’s edge, i.e., 7cm.

Radius (r) of hemispherical part = `7/2` = 3.5 cm

Total surface area of solid = Surface area of cubical part + CSA of hemispherical part − Area of base of hemispherical part

= 6 (Edge)2 + 2πr2 - πr2  

= 6 (Edge)2 + πr2

Total surface area of solid = `6(7)^2 + 22/7 xx 7/2xx 7/2`

= 294 + 38.5

= 332.5 cm2

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अध्याय 12: Surface Areas and Volumes - EXERCISE 12.1 [पृष्ठ १६६]

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एनसीईआरटी Mathematics [English] Class 10
अध्याय 12 Surface Areas and Volumes
EXERCISE 12.1 | Q 4. | पृष्ठ १६६

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