Icing on the cake

Difficulty:
higher

Rating:
4-stars

GCSE Marks:
5-marks

GCSE Text:
Three identical cylindrical cakes were made with icing applied to the top and sides. Here is the design of one of the cakes:

christmas cake.png

a) What area of icing was required to cover the top and sides of one cake?

Icing was bought pre-made in packs, and each pack contained a block that was simply rolled into shape, covering an area of 30cm x 50cm.

b) How many packs of icing were needed to cover the three cakes?

Suggestions:
This video is a very festive example of a cooking calculation, but one that requires students to recall and understand calculations for area and circumference of a circle. The second part of the question may look challenging, but requires simple arithmetic to compare areas.  This problem works well as a consolidation task and normally takes students around 5 – 6 minutes to solve.

Extension Ideas:
Teachers could extend the learning by considering:

  • A mathematically similar cake tin was used to make a separate cake to give to a friend. This height of this cake measures 4.5cm. What area of icing would be needed to cover this smaller cake?  Explain why it isn’t half of the icing area of the larger cake.

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