You match the point up to the black line and sew, then flip it over and sew the other side.
Then you just cut it down the middle and iron and boom, boom, pow! Look at all the triangles I made in 30 minutes!! I didn't count the triangles but there enough to go around a twin size quilt. Now do you see how I am able to get things done around here? I'm always trying to find the fastest way to do things.