Hi Apaul466,Thanks for another question! Apologies for the slow reply; I was dealing with some technical issues.I think this question can’t be done much quicker, at least from the way I see it. You should be able to comfortably do it in under 3 minutes if you know a certain rule. The diagonal of a square with base x is just root(2) times x. This little fact speeds up calculating the initial diagonal of the square base - I have shown it in my workings below. From here it is just how confident you are with your mental arithmetic. Given that A-Level Maths is all calculator, mental arithmetic is not so much an essential skill as it was at GCSE. Keep the questions coming!
Hi Apaul466, Thanks for another question! Apologies for the slow reply; I was dealing with some technical issues. I think this question can’t be done much quicker, at least from the way I see it. You should be able to comfortably do it in under 3 minutes if you know a certain rule. The diagonal of a square with base x is just root(2) times x. This little fact speeds up calculating the initial diagonal of the square base - I have shown it in my workings below. From here it is just how confident you are with your mental arithmetic. Given that A-Level Maths is all calculator, mental arithmetic is not so much an essential skill as it was at GCSE. Keep the questions coming!