calculate area in c#

hi. i want to write a cod for my corel document to calculator my shape area. but i want this soft calculate area and minus the hole of that. for example if my squar is 4 cm3 and in that i have 1 cm3 another squar the app calculate that and say total area is 3cm3.

please help me.

i calculated area with cdr.activeshape.curve.area but this cand calculated total area.