Class 9 Maths Question Answers - Surface Area and Volume of a Right Circular Cylinder

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Q u e s t i o n : 4 7
Write the number of surfaces of a right circular cylinder.
S o l u t i o n :
Let us list out the surfaces of a right circular cylinder.
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Q u e s t i o n : 4 7
Write the number of surfaces of a right circular cylinder.
S o l u t i o n :
Let us list out the surfaces of a right circular cylinder.
1. Lateral surface
2. Lower circular base
3. Upper circular covering
Therefore, a right circular cylinder has a total of 3 surfaces.
Q u e s t i o n : 4 8
Write the ratio of total surface area to the curved surface area of a cylinder of radius r and height h.
S o l u t i o n :
Total Surface Area of a cylinder = 
Curved Surface Area of a cylinder = 
Ratio of Total Surface Area
TSA to Curved Surface Area
CSA is given by,
The ratio of Total Surface Area to Curved Surface Area is
h +r: h
Q u e s t i o n : 4 9
The ratio between the radius of the base and height of a cylinder is 2 : 3. If its volume is 1617 cm
3
, find the total surface area of the cylinder.
S o l u t i o n :
Given data is as follows
We have to find the total surface area of this cylinder
It is given that 
Therefore 
Therefore;
(As )
So;
Therefore;
Q u e s t i o n : 5 0
If the radii of two cylinder are in the ratio 2 : 3 and their heights are in the ratio 5 : 3, then find the ratio of their volumes.
S o l u t i o n :
Let r
1 
and r
2 
be the radii of the two cylinders respectively and h
1 
and h
2
 are the heights of the two cylinders respectively. It is given that  and 
We are asked to find the ratio of the volumes of the two cylinders
Now;
Therefore the ratio of the volumes of the two cylinders is