corel draw 12 corner roundness Unit??

I have rounded off the corners of a rectangle, however I have no idea what the unit is? All it says is corner roundness is 16. Doesn't give me a unit, degrees don't work, radians don't seem right, arc length would be way to long as i have a part that is 3inches by 5 inches. I have found nothing that shows me a unit or anything? Can someone pleas help, as this is hooked up to a laser cutter. I need to convert these drawings over to solid works for documentation. Without doing so, I won't be able to get apropos drawing