two circles are tangent externally to a third circle at A and are tangent internally to a third circle at A and D. if BC is the common internal tangent and equal to 20 cm. find the area of the shaded portion

1^stline of the question is not clear. Two circles are tangent externally at what points.
What is the shaded region.
Please take the photo of the question & upload it so that the question is clear.
If you cant take the photo, then you have to clearly explain the region to which you are asking to find the area.