Looking for a quick tip on removing part of circle

[Anonymous]

So I have this sketch and I am trying to make the parts I have highlighted in red disappear so when I do a 2d contour to cut out it doesn't try the cut the whole circle and instead just continue onto the flat middle piece and soo-on. Any suggestions would be appreciated.

[TheCADWhisperer · Accepted solution]

Trim.

Do I see blue curves and a white dot?  Not good!

[Anonymous]

Yup, that did it. 

 Thanks