A school is using an inflatable movie screen during an outdoor event. To ensure the inflatable movie screen is sturdy, a piece of string attached to the screen is hammered in the ground using a stake, shown below.



The ground, screen, and string create a right triangle. The screen is 9 feet tall and the string is 15 feet long.

If x is the distance, in feet, along the ground from the stake to the screen, what is the value of x ?

Enter the value of x in the box.

x=