SOLIDWORKS Design & Help

You have multiple dimensions angles, radius, height and width in this file. You can easily identify the diameter or radius.

I provided the solution to this over here:

https://grabcad.com/groups/technical-drawing-drafting/questions/i-need-help-with-this-drawing

The drawing provides all the information necessary, if you properly constrain the sketch.

You can Insert the drawing as a Sketch Picture and scale it properly and find the missing dimension!

That dimension is not required to fully define the profile the profile.

Yep, I saw your link and you are right, however what the was missing here is the extension line that you show as amber 👍

Yes but care must be taken in using self instincts to judge results dimensions.

When there are no blue lines it means the sketch is fully defined so the diameter is already set.