If I have a ComponentDefinition from which I get a list of instances how do I get the position of each instance?

I need to interrogate a plane and need to know what what the values mean.

entity.plane

I noticed that if I have the plane at 45deg then I get a value of 0.707106781186547 I do not know what that means. I also see there are 4 values what are they? I can understand x, y, z but I am not sure of the 4th item in the array.

Thanks

Thanks once I used to_m I got the correct value.

I create an arc with a Radius of 5M on my drawing. Then when I read that value through Ruby I get either a value of 196 or 180 and I am not sure of the units. The length is also wrong. I find the edge then I get the curve off the edge then I get the radius from the curve.

entity.curve.radius.to_s

Any ideas how to get the correct value?