By 1900, how much of the world’s railroad tracks were in the United States?

I don't know if this is right but i think 215,000 miles of railroad.

Explanation:

answer: this problem has only trivial solutions, with all points on the same line. x=5 or x=7/5.

step-by-step explanation:

there are three triangles, and three unknowns: x, y=length of middle segment, and z=cos(angles marked with red arc).

we need

and law of cosines,

the three equations are

see attached image for solution.