the complete question in the attached figure
we know that
If two chords intersect in the interior of a circle, then
the product of the lengths of the segments of one chord
is equal to the product of the lengths of the segments of
the other chord (Segments of Chords Theorem)
therefore
AB*BC=DB*BE
AB=x
BC=x
DB=62
BE=250-62---------> BE=188 ft
so
x*x=62*188----------> x²=11656--------> x=√11656--------> x=107.96 ft
the answer is x=107.96 ft