Area of the region enclosed by two touching discs and a common tangent

Two circular discs, with centres \(A\) and \(B\) and radii \(6\text{ cm}\) and \(3\text{ cm}\) respectively, touch each other. A straight line touches the larger disc at \(P\) and the smaller disc at \(Q\), as shown in the diagram.

Find the area of the shaded region, which is enclosed by the line segment \(PQ\) and the two discs.[6]