[css-round-display] The interpolated property type for animatable polar-angle

I'm editing the round display spec to be FPWD, and wondering what could be a
type for the animatable polar-angle.

 

I found interpolated property types for animation as follows.

https://drafts.csswg.org/css-transitions-1/#interpolated-types

 

Both a length and a percentage are obvious as the polar-distance's
animatable type, but I couldn't find the angle type in above link. Is number
the right type to specify polar-angle's animatable type?

 

BR,

- hyojin