A bridge is built in the shape of a parabolic arc and is to have a span of 100 feet. The height of the arch at a distance of 40 feet from the center is to be 10 feet. Assume that the ground is the x-axis and the y-axis as the axis of the arc.

a. How high is the arch at its center approximated in two decimal places?

b. What is the horizontal length, approximated to two decimal places, of the arch from axis when it’s 15 feet high?