Question

A bottle of lotion is shaped like a cylinder with a radius of 3 cm and a height of 12 cm. The empty tube inside the cylinder has a radius of 0.5 cm and is the same height as the bottle.
What is the volume of the lotion in the bottle? Use 3.14 to approximate pi, and express your answer to one decimal place.

Answer 1

So we know the equation to find the volume of a cylinder is
Volume of cylinder = πr^2h
where r is radius and h is height.

For the bottle of lotion, we are given a radius of 3cm and a height of of 12cm.
Sub these numbers into the equation:
Volume of bottle = 3.14*3^2*12
Therefore we get 339.12cm^3

For the tube in the bottle, we are given a radius of 0.5cm and a height of of 12cm.
Sub these numbers into the equation:
Volume of bottle = 3.14*0.5^2*12
Therefore we get 9.42cm^3

To find the volume of the lotion we have to take the total volume in the bottle by the volume in the tube.
=339.12 - 9.42
=329.7cm^3

Note: Don't round your number earlier on, always round at the end but in this case the answer came exactly to one decimal places.