Surface Area of a Right Circular Cylinder


Surface Area of a Right Circular Cylinder


If we fold a rectangular sheet with one side as its axis then it forms a cylinder. It is the curved surface of the cylinder. And if this curved surface is covered by two parallel circular bases then it forms a right circular cylinder.





Right Circular Cylinder – with radius  and height 



Curved Surface area = 



Total surface area = 


Surface Area of a Hollow Right Circular Cylinder


If a right circular cylinder is hollow from inside then it has different curved surface and volume.




Hollow Cylinder


Each base surface area = 



Curved surface area = 



Total surface area = 


Example


Find the Total surface area of a hollow cylinder whose length is 22 cm and the external radius is 7 cm with 1 cm thickness. (π = 22/7)


Solution


Given, h = 22 cm



R = 7 cm



 r = 6 cm (thickness of the wall is 1 cm)



Total surface area of a hollow cylinder = 2πh(R + r) + 2π(R²- r²)     



= 2(π) (22) (7+6) + 2(π)(7²- 6²) 



= 572 π + 26 π = 598 π



= 1878.67 cm²