How do I constrain an arc?

[HuntleyBill]

OK, I know this probably simple as hell but I am not seeing it. I drew up a very simple drawing (attached). I can constrain everything except the arcs on the outer corners. For the life of me, I can't figure out how to constrain the 4 arcs.

[g-andresen]

Hi,

try this way:

günther

[o.briggs.1]

Cant access the file at the moment as I am on my phone but I can’t see any dimensions. You probably need to constrain the radius value (ie add a dimension to the sketch to define the arc radius. 
An arc needs to be constrained in position (sometimes at both ends or other times from a central radius) and then it needs a radius constraint. 
a good way to figure out what needs to be added to constrain a sketch is to click and drag on the sketch line. It moves when not constrained and by looking at how it moves you can see how you need to constrain it further. Try dragging one or the lines. If the arc gets bigger and smaller but doesn’t move from it’s end points; you need to add a radius dimension. 
you could also constrain it from this by adding tangent constrained to construction lines perpendicular to each line, but a dimension is probably easier. 
when you add the dimension, the value should already be correct (if your arcs are already in the right place) so just add one and don’t change the number 🙂 

[HughesTooling]

Best practice is don't trim the square, unless you really the square with the corners removed. The sketch below will extrude just the same as yours. Try and keep your sketches as simple as possible, like this. File's attached.

Mark

[etfrench · Accepted solution]

Here's another option with fewer steps and less clutter:

[HuntleyBill]

Wow. Thank you all.