midpoint of an elliptical arc

Hi,

I want to find the midpoint of an elliptical arc.

I have the following input

1. Start point of elliptical arc

2. End point of elliptical arc

3. Center point of elliptical arc

4. Angle between center and start point of elliptical arc

5. Angle between center and end point of elliptical arc

6. Distance between center and start point of elliptical arc

7. Distance between center and end point of elliptical arc

Can you sort out a procedure to find the midpoint of an elliptical arc from above input?

Thank you

M Rajee