Let’s first start by realizing that it is perimeter, so it will have to have two different numbers. 56 divided by 4 is 14, this would make it a square. So then you start plugging in numbers.
L W
15 13
17 11
.................
Do this again until you get to a point where the Length is 3 times more than the width.
19. 9
21. 7
DING DING DING
The length is three times more than the width so the dimensions of the room is 21 by 7.
21+21+7+7=56 meters
:)