Hi all, this question has likely been asked (and solved) many times. However, I don't understand the terminology enough to find relevant results.

I am getting a custom property using:

bbArea = swFeat.CustomPropertyManager.Get6("Bounding Box Area", False, bbArea, bbAreaOut, True, False)

The line returns property as desired, let's say 100", as expected. However when I try to do any algebra, I get a mismatch error. I need to multiply it by a percentage, as the idea is to calculate waste. 

Since the dim 'bbAreaOut' is a string, what type is needed for algebra?

Also, this process, what is it called? Dimensional transformation/conversion?