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From a solid cylinder whose height is 2.4 cm and diameter 1.4 cm, a conical cavity of the same height and same diameter is hollowed out .find the total surface area of the remaining solid to the nearest cm².
{{ chapter - 13, ex.13.1 , question no. 8 }}
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vishal6012:
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t.s.a of remaining solid nearest =18cm^2
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Hlo mate :-
Solution :-
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Given
Height of cylinder = Height of conical cavity, h = 2.4 cm
Diameter, d = 1.4 cm
Radius, r = 1.4/2= 0.7 cm
Slant height, l = √h² + r² = √(2.4)² + (0.7)² = √5.76 + 0.49 = √6.25 = 2.5 cm
TSA of the remaining solid = CSA of cylindrical part + CSA of conical part + Area of cylindrical base
TSA = 2πrh+ πrl+ πr²
= πr [ 2(h) + l + r ]
= 22/7 × 0.7 [ 2 × 2.4 + 2.5 + 0.7 ]
= 17.6 cm²
Hence,
TSA of remaining solid is = 17.6 cm²
:- when rounded off = 18 cm^2 ans
_________________________________________________________________________________________________
Hope it's helpful
Solution :-
_________________________________________________________________________________________________
Given
Height of cylinder = Height of conical cavity, h = 2.4 cm
Diameter, d = 1.4 cm
Radius, r = 1.4/2= 0.7 cm
Slant height, l = √h² + r² = √(2.4)² + (0.7)² = √5.76 + 0.49 = √6.25 = 2.5 cm
TSA of the remaining solid = CSA of cylindrical part + CSA of conical part + Area of cylindrical base
TSA = 2πrh+ πrl+ πr²
= πr [ 2(h) + l + r ]
= 22/7 × 0.7 [ 2 × 2.4 + 2.5 + 0.7 ]
= 17.6 cm²
Hence,
TSA of remaining solid is = 17.6 cm²
:- when rounded off = 18 cm^2 ans
_________________________________________________________________________________________________
Hope it's helpful
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