If you wanna learn this .. if you see a side that looks exactly the same put the same number... there for ex : number 2 has one 9 add the 9 from the opposite side so you have 18 now. Next 42-18=24. Afterwards divide 24 by the numbers of side you haven’t figured out so 24/2=12 so your answer is 12 for length.
Since 42= 2l + 2h, and l is 9, then 24=2h, h=12. Since 28=4 x h then h is 7. Area is base times height and since the height is 25, it can be said that 200=25b and b=8
