Question

What is formula for calculating hollow surface area of a cylinder?

Answer 1

 2 π r (r + h)
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r = radius

h = height 

π = 3.14 or 22/7
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 2 π r (r + h)  is formula for calculating hollow surface area of a cylinder

Answer 2

HELLO FRIENDS,
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The formula for calculating hollow surface area of a cylinder = 2 π r (r + h)

Where 
r=radius
h=height
$\pi =3.14$
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Best of luck ;)
ROYALJATT