By size do you mean the area?
There are a couple of ways to find this out. The fastest is to select the object(s), one or both
Window>Palettes>Element Information
You can get 2d and 3D info here.
HTH
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"