Explanation
Curved surface area of a cylinder of radius "R" and height "h" is 2\pi Rh.
Given, curved surface area =44,4 m^2Therefore, CSA of the given cylinder = 2\times \dfrac {22}{7} \times 0.7\times h = 4.4 sq.cm
\Rightarrow \dfrac {44}{10}=\dfrac {44}{7}\times \dfrac {7}{10}\times h
\Rightarrow h = 1 m
Hence, option 'A' is correct.
Given, radius r=10.5 cm.
We know, the surface area of a sphere of radius r = 4\pi { r }^{ 2 }
= 4 \times \dfrac {22}{7} \times 10.5 \times 10.5
= 1386 {cm}^{2} .
Therefore, option A is correct.
Given, radius r=5.6 cm.
We know, the surface area of a sphere of radius r= 4\pi { r}^{ 2 }
= 4 \times \dfrac {22}{7} \times 5.6 \times 5.6
= 394.24 {cm}^{2} .
=> 4 \times \cfrac {22}{7}\times { r }^{ 2 } = 154 {cm}^{2}
=> { r }^{ 2 } = \cfrac {49}{4} =\cfrac {7}{2} cm Volume of a sphere = \cfrac { 4 }{ 3 } \pi { r }^{ 3 }
= \cfrac {4}{3} \times \cfrac {22}{7} \times \cfrac {7}{2} \times \cfrac {7}{2} \times \cfrac {7}{2} = 179 \cfrac {2}{3} {cm}^{3}
Surface area of a sphere of radius r = 4\pi { r }^{ 2 }
= 4 \times \dfrac {22}{7} \times 7 \times 7
= 616 {cm}^{2} .
Radius of the spherical ball = \cfrac {28}{2} = 14 cm
The amount of water it displaces is equal to its volume.
Volume of a spherical ball = \cfrac { 4 }{ 3 } \pi {r }^{ 3 }
'= \cfrac {4}{3} \times \cfrac {22}{7} \times 14 \times 14 \times 14
= \cfrac { 34496 }{3} = 11498\cfrac 23 {cm}^{3}
Given, surface area of sphere =154 cm^2
Surface area of a sphere of radius 'r' = 4\pi { r }^{ 2 } = 154
\Rightarrow 4 \times \dfrac {22}{7} \times { r }^{ 2 } = 154 {cm}^{2}
\Rightarrow { r }^{ 2 } = \dfrac {49}{4}
\Rightarrow r = \dfrac {7}{2} = 3.5 cm.
Total surface area of a cylinder of Radius "R" and height "h" = 2\pi R(R + h)Radius of the base of the cylinder = \dfrac {28}{2} = 14 cm
Hence, total surface area of the cylinder =2\times \dfrac { 22 }{ 7 } \times 14(14 + 20)
= 2992 cm^2
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