[Solved]how i can use a yellow dimensions in a equalisation?

[aginor]

I draw 2 circles that tangent from each other with diameter 20 mm. The dimension outside to outside is 40 mm but is yellow. That I can use him in an equation? In this example it is diameter on 2, but in other cases it is complex the determination.

[Pieter]

You can create a parameter based on a distance or a dimension.
Use the "bue" parameter function. (Next to the blue point).

Best regards