Answer: 32 sq.cm
Explanation:
If you think of it as there being 2 squares instead of 1, you can think well since the whole one side of the rectangle is 8cm and the half side is 4 then that must mean that the other square that you just divided up must be 3 by 4 so then you can multiply those and get 12 and you do the same for the other one which would be 4 by 5 and when you multiply those you will get 20 and when added you get 32. Hope this helps :)