Final answer:
To find out how much longer the new moat is, calculate the perimeters of both moats and find the difference. The old moat was 60 feet and the new moat is 72 feet, so the new moat is 12 feet longer.
Step-by-step explanation:
The subject of the question is to calculate the difference in the perimeter of two different-sized moats around a sandcastle. To solve this, we will calculate the perimeter of the old moat and the new moat and then find the difference between the two.
The old moat's perimeter is calculated by doubling the length and width of the old sandcastle and adding them together: 2 × 19 ft + 2 × 11 ft = 38 ft + 22 ft = 60 feet. The new moat's perimeter follows the same logic: 2 × 12 ft + 2 × 24 ft = 24 ft + 48 ft = 72 feet. The difference in the length of the two moats is therefore 72 ft - 60 ft = 12 feet longer.