An inscribed circle problem (Posted on 2006-12-31)

A circle is inscribed in a quadrilateral ABCD in such a manner that the circle is tangent to all the four sides of the quadrilateral. It is given that Angle BAD = 90^{0}= Angle CBA.

Find the radius of the circle given that: BC = 21 units and AD = 28 units.

What would be the radius of the inscribed circle if BC = 36 units and AD = 45 units?