$A$: The area of a circular segment with chord of length $b$, and height $h$.
$B$: The area of the isosceles triangle inscribed into the shape described in A.
Find of the limit of $A/B$ when the arc angle tends to $0$, then use that limit to approximate the area of a circular segment.
My main confusion with the question comes from the fact that to find the specified limit, I will need to use the formula for a circular segment, which is what im trying to prove in the first place.