A certain bridge arch is in the shape of the top half of an ellipse 144 feet wide and 34.7 feet high. At what horizontal distance from the center of the arch is the height equal to 12.6 feet? Give your answer accurate to 2 decimal places.

feet

Box 1: Enter your answer as an integer or decimal number. Examples: 3, -4, 5.5172
Enter DNE for Does Not Exist, oo for Infinity