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**Cylinder**

A cylinder is a solid object having curved surface with
two circular faces of same size. Measuring jars, circular pillars, circular
pipes, gluesticks etc. are some examples of cylinder. A cylinder is also called
a circular prism. The figure given below is a cylinder.

Where,

AX = BY = r = radius of cylinder

AB = XY = h = height of cylinder

XY = axis of cylinder

If the axis of cylinder is perpendicular to the circular
base then the cylinder is called a right circular cylinder, otherwise it is
called an oblique cylinder.

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**Net of right circular cylinder**

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**Formula
for surface area and volume of right circular cylinder**

Curved surface area (CSA) of cylinder = 2πrh

Total surface area (TSA) of cylinder = 2πr(r + h)

Volume of cylinder = πr

^{2}h###
**Hollow
Cylinder**

A hollow cylinder is a solid bounded by two co-axial
cylinders of the same height and different radii. For example - water pipe,
rubber pipe etc. The figure given below is a hollow cylinder where R is
external radius and r is the internal radius.

i. Area of base ring = πR

^{2}– πr^{2}= π(R^{2}– r^{2})
ii. Curved surface area of hollow cylinder =
External surface + Internal surface

= 2πRh + 2πrh

= 2πh(R + r)

iii. Total surface area of hollow cylinder =
Curved surface area + 2 Area of base ring

= 2πh(R+r) + 2π(R

^{2}–r^{2})
= 2πh(R+r) + 2 π(R+r) (R–r)

= 2π(R+r) (h+R–r)

iv. Volume of the material used in hollow
cylinder = External volume – internal volume

= πR

^{2}h – πr^{2}h
= πh(R

^{2}– r^{2})

*You can comment your questions or problems regarding cylinder here.*

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