Question

A hollow metallic cylinder is open at both the ends is of length 8cm if the thickness of the metal is 2cm and external diameter of the cylinder is 10cm. Find the whole curved surface area of the cylinder. ( use ^ = 3.14 )

Answer 1

Answer:

We know, C.S.A. of hollow cylinder = (internal surface area + ext. surface area)

so, C.S.A. = (2pie×r×h + 2pie×R×h)

external radius = R

internal radius = r

A.T.Q.:-

h = 8cm

R = 10/2cm = 5cm

r = 5cm-2cm=3cm(thickness of cylinder is 2cm)

Now,

Internal surface area:-

= 2pie×r×h

= 2×3.14×3×8

= 6.28×24

= 140.72 cm square ------ ( i )

Now,

External surface area:-

= 2pie×r×h

= 2×3.14×5×8

= 6.28×40

= 251.2 cm square ------- ( ii )

ADDING EQUATION (I) AND (II) WE GET:-

= (251.2+140.72) cm square

= 391.82 cm square. -----------------ANS.

THANK YOU...............

Please mark my answer as brainiest

Answer 2

Answer:

401.92

Step-by-step explanation:

Given : length of cylinder = 8cm

thickness of cylinder = 2cm

External diameter = 10cm

so, external radius = 10/2 = 5

and internal radius = 5-2 = 3

internal curved surface area = 2 pie rh

= 2*3.14*3*8= 150.72square cm

external curved surface area = 2pie rh

= 2*3.14*5*8 = 251.2 square cm

whole curved surface area = internal curved surface area + external curved surface area

= 150.72 + 251.2 = 401.92