Answer:
600 feet
Explanation:
I am assuming that the park is rectangular, and the together, the length, with and diagonal form a right triangle.
In this case, we are given
Diagonal = 750 ft = hypotenuse
Width = 450 feet
Find length L
Using the Pythagorean theorem,
L² + 450² = 750²
L² = 750² - 450² = 360,000
L= √360,000 = 600 feet