Question

find the total surface area of a hollow cylinder open at both ends,if it length is 28cm external radius is 7cm and thickness is 1 cm

Answer 1

TSA = 2π(R-r)h
Thickness =external radius-internal radius
Thus,r=6cm
TSA=2*22/7*1*28=176cm^2
Tell me if it's right
Cheers☺️

Answer 2

Answer:

2369.71

R= 7 cm

r= 7-1

= 6 cm.

h= 28 cm

T.S.A= 2π(R+r)(h+R-r)

=2×22/7(7+6)(28+7-6)

= 44/7×13×29

= 16588/7

= 2369.71 cm^2