Christmas MT's answer to RENUGA's Primary 6 Maths Measurement Singapore question.

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Christmas MT
Christmas Mt's answer
3427 answers (A Helpful Person)
Hope this is understandable!

I tried to 'open up' the cuboid to show the three areas on a flat surface to try to help the visualisation.

The main bulk of work is seeing that the area comparison of the three surfaces actually shares a common geometry, such as A and B both having same L (length), A and C both having same B. Then using ratio, and the value of H given, we can work towards the answer.