When an airplane travels faster than the speed of sound, the sound waves form a cone behind the airplane. If the airplane is flying parallel to the ground, then the sound waves intersect the ground in a hyperbola with the airplane directly above its center, and a sonic boom is heard along the hyperbola. You hear a sonic boom that is audible along a hyperbola with the equation (x2 / 100) − (y2 / 4) = 1, where x and y are measured in miles. What is the shortest horizontal distance you could be from the airplane?