How to reference arc's angle?

[michael8WNBX]

I'm trying to sketch two arcs. Say the first arc has a radius of 100 mm and describes a 90 degree arc.  Fusion 360 will let me set the second arc's radius to the first arc's radius +/- some offset by setting the second arc's radius to d1 +/- offset.  For example if the first arc's radius dimension is d1: 100, I can enter d1-5 to set the second arc's radius to 95.  If I alter the first arc's radius, the second arc follows suit.

What I can't figure out is how to say I want the second arc's angle to be the same as the first arc's angle +/- some degrees.  So if I wanted to set the second arc's angle to 30 degrees larger than the first arc's I want to be able to enter dx+30 where dx is 90 degrees, the first arc's angle. I can't figure out to find "dx". I've tried right clicking the arc while in dimension mode, center mouse clicking and ctrl clicking all to no avail.

Is the degree measure not referenceable? 

[HughesTooling · Accepted solution]

You'll need to draw 2 construction line then add an angle between them. If you have the lines already but have a constraint, for example a perpendicular constraint you need to delete the constraint and replace you a dimension.

Mark