WeBWorK using host: https://math-webwork3.unl.edu, format: simple seed: 123567890

A bridge over a river is supported by a single semicircular arch. The diameter of the semicircular arch where the bridge meets the river is 24 feet wide. The roadway is 4 feet above the center of the arch. What is the vertical distance between the roadway and the arch 6 feet from the center? (In the image, , , .)
The vertical distance is feet.