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Tin Tight

Stage: 4 Challenge Level: Challenge Level:2 Challenge Level:2
What are the most efficient proportions for a tin of paint?

"Efficient" could mean different things from different points of view - maybe start by trying to minimise the amount of material needed to make a tin with that volume.

What is the best diameter and height for a tin that contains $1$ litre of paint?

What about a $5$ litre tin?