First, how to add images to your post (without using links that make your posts get moderated...)
third, your problem.
Try the command REGEN first, that updates your display.
I see two ways to solve your issue, and what is the right one depends on how the assignment looks. Either you use MOVE and move the notch so that it intersects with your circle. Make sure that you have OSNAP (particulary ENDpoint and APParent intersection) on. Snap to the Endpoint of the notch when you are asked for Basepoint and then slowly move your cursor downwards toward the circle and you should see the Apparent Intersection OSnap.
The other way is to use the EXTEND command and extend the lines to the circle. This makes the lines slightly longer though, so like I said, depending on what the assigment says (what is actually measured), this might be wrong.