Answer:
The perimeter of an isosceles trapezoid is the sum of the lengths of all four sides. Let x be the length of the two remaining sides. Then, the perimeter of the trapezoid is:
Perimeter = 1.6 + 10.3 + x + x = 12.2 + 2x
We know that the perimeter is 51.1 miles, so:
12.2 + 2x = 51.1
Solving for x, we get:
2x = 38.9
x = 19.45
Therefore, the length of the two remaining sides is 19.45 miles.