Question

The volume of a cylindrical pipe is 1408 CM. It's length is 14cm and it's external diameter is 18cm. find its thickness

Answer 1

given,
volume of cylinder = 1408cm³
outer diameter = 18cm
outer radius = 9cm
height = 14cm
we know that,
total volume of cylinder = πr²h
= 22/7 × 9² × 14
= 22 × 81 × 2
= 3564cm³
inner volume = total volume - given volume
= 3564 - 1408
= 2156cm³
.•. to find inner radius,
inner volume of cylinder = 2156cm³
πr²h = 2156
22/7 × r² × 14 = 2156
r² = 2156/14 × 7/22
r² = 98/2
r² = 49
r = √49
r = 7 cm
hence,
thickness = outer radius - inner radius
= 9 - 7 cm
= 2 cm