Answer:
the newer moat is 169 cm longer than the older one
Step-by-step explanation:
in order to find the difference in length of the two castles, we will first find the perimeters of the two castles then calculate the difference in the perimeters:
old castle:
dimension = 484cm by 386cm
perimeter = 484 + 386 = 870 cm
new castle:
dimension = 725cm by 314cm
perimeter = 725 + 314 = 1039 cm
difference = 1039 - 870 = 169 cm
The total length of the moats used is equals to the perimeter of the sand castles, therefore, the newer moat is 169 cm longer than the older one.