• Warm-up
• Try this next
• Think higher
• Read: mathematics
• Read: science
• Explore further

Toby is 2 tomorrow and he wants a big sticky chocolate cake for his party! The problem is that my recipe specifies a 20cm round tin with a depth of 7.5cm, but I haven't got a 20cm round tin.

I do have a 23cm round tin, and I've also got a square tin, which has a side length of 15cm and a depth of 6 cm.

Which one do you think would be best?  Or should I go out and buy a new cake tin?