First, we need to find the area of the park before the expansion. We can do this by finding the length of one side of the square and then squaring it:
Length of AB = 3 - 0 = 3
Area of ABCD = (Length of AB)^2 = 3^2 = 9
Now, we need to double the length and width of the park. This means that the new coordinates of the vertices will be:
A: (0, 6)
B: (6, 6)
C: (6, 0)
D: (0, 0)
To find the area of the new park, we again need to find the length of one side of the square and then square it:
Length of AB = 6 - 0 = 6
Area of new park = (Length of AB)^2 = 6^2 = 36
Therefore, the area of the park after the length and width are doubled is 36 square units.