well at work (as a civil engineer designing streets and sewage systems) i use autocad. If i want to get areameasurements i generally create a polyline first and ask autocad for its area instead of using the normal area calculation so that i will still have the polyline later to check or change.
Granted this normaly does not include arcs. But it is a good reason to have polyline-areas available.
Right now i am sitting at home wondering if i got a calculation right and wanted to check the area which is part of the calculation by simply drawing and measuring it.
Approximation here is no use: someone else had calulated that to 0,098 and i get 0,110... well i'll just have to believe my own calculation then and check tomorrow in the office