The perimeter of a polygon is proportional to its side so:
18 : 16
24 : p
p = 21.3 meters
Area is proportional to the square of the side of a polygon so:
18² : 1000
24² : x
x = 1,777.8 square meters
Note: The value of the perimeter should not be less than the length of one side. The data may be incorrect. Regardless, the method will be the same.