For a hemisphere of radius [math]r[/math], determine a formula for the cross-sectional area created at height [math]h[/math] by the horizontal plane shown in the diagram.
[list=1] [*]Determine a formula for the radius [math]s[/math] of the circular cross section created at height [math]h[/math] of the hemisphere. [*]Use the resulting value for [math]s[/math] to find a formula for the area of the circular cross section shown in the diagram. [/list]