I don't understand very well your question, but...
1) (preferd for me) I define an equation like that: "MyDrivenDimensionName" = value (Ex: "Height" = 1870). After that I use the name of my driven dimension in other equations (MATE DISTANCE(S) or PATTERN parameters or...);
2) I sketch a line (or circle or...)with a certain length (radius ...). After that I use this line (cyrcle) especialy for equal dimensions (with my line or with the radius of my circle);
3) It is an other posibility if you use DESIGN TABLE. You can put in some cells your driven dimensions and perform calculations using EXCEL facilities.
Hope that help you but I am sure that exist many other posibilities.