Question

hollow cylindrical tube open at both ends is made up of iron 3 cm thick if the external diameter 56 cm and the length of the tube is 182 cm find the number of cubic centimetre in it

Answer 1

Answer:

Given, thickness of iron =3cm

          external diameter = 56cm

          Length of tube = 182cm

We know,

  volume of hollow cylinder = πh(R²−r²)

∴ internal diameter = external diameter−2×thickness of iron

                               = 56−2×3

                               = 56−6

                               = 50cm

=> Outer radius(R) = 56÷2 = 28cm

       inner radius(r) = 50÷2 = 25cm

Volume of hollow cylinder = πh(R²−r²)

                                        = 3.14×182(28²−25²)

                                        = 3.14×82×159

                                        = 90865.32cm³