Answer:
5 km would be the answer
Explanation:
For 45-45-90 triangles, the values are x, x, for the less long sides, then for the hypotenuse it's x sqrt2, because that is the rule for 45-45-90 triangles. So since in this problem, the value for the hypotenuse is 5sqrt2 km, the c value would be 5 km. Hope this helps!