To find the length of the edge of the square base, let's use the Pythagorean theorem.
The Pythagorean theorem states that the square of the length of the hypotenuse (in this case, the slant height) is equal to the sum of the squares of the lengths of the other two sides (in this case, the height and the length of one edge of the square base).
So, we have:
slant height^2 = height^2 + edge length^2
Replacing the values given in the problem:
436.5^2 = 321^2 + edge length^2
Simplifying:
191,202.25 = 103,041 + edge length^2
Subtracting 103,041 from both sides:
88,161.25 = edge length^2
Taking the square root of both sides:
edge length ≈ √(88,161.25) ≈ 297.0 feet
Therefore, the length of the edge of the square base is approximately 297.0 feet, rounded to the nearest tenth.