A bridge is built in the shape of a semielliptical arch. It has a span of 106 feet. The height of the arch 25 feet from the center is 5 feet. Find the height of the arch at its center.

Now I'm pretty sure what I can do is 25^2/11236 + 5^2/b^2 = 1

so.. 625/11236 + 25/b^2 = 1

then solve for b

is this correct??