Consider two pieces of railroad track, each one kilometer long, laid end to end (see figure). The tracks are nailed down at their endpoints but simply meet in the middle. In summer, the railroad tracks expand, each by one centimeter. Since they are attached to the ground at the end points, the tracks can only expand by rising like a drawbridge. Furthermore, these pieces of track are so sturdy that they remain perfectly straight as they go up.
What is x? In other words, by how much does the track rise above the ground?
Please enter your answer in centimeters. If your answer is 1 cm, enter “1”. If your answer is 1 meter, enter “100”.