Answer: I believe that the remaining four sides have 6 meters of fencing each.
Step-by-step explanation:
You have 54 meters of fencing for 6 sides of a dog pen. Two of these are 15 meters long each. 2 times 15 equals 30, so that makes the remainder of the fencing 24 meters (54-30=24). After that, there are 4 sides left to the fence, so 24 divided by 4 equals 6 (24÷4=6), and that is your answer
Hope this helps!