Difficulty: Rating: GCSE Marks:

GCSE Text:
The diagram below shows the design of a circular pond with a central island.

Calculate the total volume of water in the pond, giving your answer in m³ and rounded to 3 sig. fig.

Suggestions:
This may look like a straight forward ‘donut’ shape volume, but students need to work backwards from a given circumference, and make sure that they convert to a standard form of units as well. This question is useful for highlighting rounding issues as well.  Students only take 3-4 minutes to answer this question in full, and the extension question work well to stretch students who finish early.

Teachers could extend the learning by considering:

• The new pump specifies volume in cm³ instead of m³. Convert the total volume answer into cm³.
• The gardener needs to install an overflow to prevent the pond from getting too deep when rain falls. If the pond volume must not exceed 4m³, what is the maximum allowable depth of water?