Question

An iron pipe is 21 cm long and its exterior diameter is 25 cm. If thickness of the pipe is 1cm, find the whole surface of pipe.
Please can a maths teacher answer this...

Answer 1

h=21cm exterior diameter=25cm ex.radius=12.5cm
Inner radius=12.5-1=11.5cm
TSA=2π(R+r)(h+R-r)
2*22/7*(12.5+11.5)*(21+12.5-11.5)
=2*22/7*24*21
=23232/7cm^2

Answer 2

The while surface area of iron pipe is 3608cm sq.