How to separate, remove these inner line shapes?

[wizard509]

Just looking at your image I would say when putting the circle in place you need to cut it so the red precisely lines up with rhe black lines, I would suggest making both the same lline weight such as 4pt and increase the zoom so you can get a clear view of how both line up then select both and slice(Ctrl 4) you can always change the lpne weight.

OK I did a tutorial as how i did it. Maybre someone else here knows a better way.

Trianglr.xar