Final answer:
The length of the main span of the Dames Point Bridge can be found by setting up the equation x = 366 + 30, where x represents the length of the main span. Solving this, we get that the Dames Point Bridge's main span is 396 meters long.
Step-by-step explanation:
To find the length of the main span of the Dames Point Bridge, we can set up the following equation:
Let x represent the length of the main span of the Dames Point Bridge. Since we know the main span of the Sunshine Skyway Bridge is 366 meters and that it is 30 meters shorter than the Dames Point Bridge, we can write the equation as:
x = 366 + 30
Solving the equation gives us:
x = 396 meters
Therefore, the length of the main span of the Dames Point Bridge is 396 meters.