formula for cylinder
Mensuration of Class 8
A cylinder is a three dimension figure .its two bases are circles and the sides of a cylinder are curve.
Solids like measuring jars, circular pillars, circular pencils, circular pipes, road rollers, gas cylinders etc., are said to have cylindrical shape. For a cylinder of base radius = r and height (or length) = h, we have
= 2πr(h + r) sq units 

HOLLOW CYLINDERS
Solids like iron pipes, rubber tubes are in the shape of hollow cylinders.
Consider a hollow cylinder having
External radius = R, internal radius = r and height = h.
Then, we have
 Volume of material = (external volume) – (internal volume)
cubic units
cubic units
 Curved surface area of hollow cylinder
= (external surface area) – (internal surface area)
 Total surface area of hollow cylinder
=(curved surface area) + (area of the base ring)
sq units
SOLVED EXAMPLES
question Find the volume of cylinder if the radius of a cyinder is 5m and its height is 10m.
Sol. Here, h = 10 m and r = 5 m.
So, volume of cylinder is = πr2h
=
= 785.71 m3
question A closed cylindrical tank of radius 8 m and height 15 m is made from a sheet of metal. How much sheet of metal is required?
Sol.Total surface area of cylinder = 2πr (r + h)
= 1156.57 m2
Thus, 1156.57 m2 sheet of metal is required.
CBSE NCERT Solutions for Class 8 Maths
class 8 maths NCERT solutions Chapter 1: Rational Numbers
class 8 maths NCERT solutions Chapter 2: Linear Equations in One Variable
class 8 maths NCERT solutions Chapter 3: Understanding Quadrilaterals
class 8 maths NCERT solutions Chapter 4: Practical Geometry
class 8 maths NCERT solutions Chapter 5: Data Handling
class 8 maths NCERT solutions Chapter 6: Square and Square Roots
class 8 maths NCERT solutions Chapter 7: Cube and Cube Roots
class 8 maths NCERT solutions Chapter 8: Comparing Quantities
NCERT Class 8 Maths solution Chapter 9: Algebraic Expressions and Identities
class 8 maths NCERT solutions Chapter 10: Visualizing Solid Shapes
class 8 maths NCERT solutions Chapter 11: Mensuration
class 8 maths NCERT solutions Chapter 12: Exponents and Powers
class 8 maths NCERT solutions Chapter 13: Direct and Inverse Proportions
class 8 maths NCERT solutions Chapter 14: Factorization
class 8 maths NCERT solutions Chapter 15: Introduction to Graphs
class 8 maths NCERT solutions Chapter 16: Playing with Numbers
Notes,worksheet and solved question for Maths class 8
 class 8 maths notes on chapter Liner equation in one variable
 class 8 maths notes on chapter algebric expression
 class 8 maths notes on chapter Mensuration
 class 8 maths notes on chapter Square and square roots
 class 8 maths notes on chapter statistice
 class 8 maths notes on chapter practical Geometry
 class 8 maths notes on chapter commericial maths
 class 8 maths notes on chapter solid shape
 class 8 maths notes on chapter quadrilaterals
 class 8 maths notes on chapter exponents
 class 8 maths notes on chapter factorisation
 class 8 maths notes on chapter inverse proporation
 class 8 maths notes on chapter cube and cube roots
Check your marks in a chapter which you have complited in school from Physics Wallah chapter wise online test just click on the link given below