Are there ways that I can constrain things to be tangent, equal, parallel when doing simple modeling?

Is there a way that I can “size” (dimension) things? I’m more of an exact person when it comes to modeling; it seems to make my life easier… but not in this case I guess.

I’ve used Inventor, Solidworks, and Rhino… and these all have constraint options.

Like… for instance… making a circle tangent to a square’s edge. Circle radius 1 and square edge length equal to the circle’s radius.

I can’t figure out where to find how to do these things. (Google and forum search has failed me.)