Question

A cylindrical pipe is 35cm long. The internal and external diameters of the pipe are 20mm and 28mm respectively. Find the volume of metal used in making the pipe, giving your answer in cubic centimetres.

Answer 1

Answer:

The volume of metal used is 105.6 cm³

Step-by-step explanation:

Height of pipe (h) = 35 cm

Internal diameter of pipe = 20 mm = 2 cm

Internal radius of pipe (r) = 2/2 = 1 cm

External diameter of pipe = 28 mm = 2.8 cm

External radius of pipe (R) = 2.8/2 = 1.4 cm

Volume of metal used = Outer Volume - Inner Volume

                                     = πR²h - πr²h

                                     = πh (R² - r²)

                                     = 22/7 × 35 (1.4 × 1.4 - 1 × 1)

                                     = 22 × 5 (1.96 - 1)

                                     = 110 × 0.96

                                     = 105.6 cm³