To determine the total length of the race course around a triangle-shaped area, you'll need the lengths of all three sides of the triangle. However, since no diagram or specific side lengths were provided in your question, I cannot calculate the total length of the race course.
If you have the lengths of the sides, you can find the total length by simply adding the lengths of the three sides together:
Total length = Side 1 + Side 2 + Side 3
If the given options in your query (17.31 km, 1.731 km, 5.754 km, 4.754 km) correspond to specific triangle side lengths that you know, please provide those lengths so that we can perform the calculation.