Using PowerPoint drawings I need to create two arrows, please see the sample image below. I want both arrows to have the same length and one arrow shall be the horizontal mirroring of the other arrow (so that one has an angle of e.g. 67.5° and the other one of 360° - 67.5°). Anyone can tell me how to do this? In case there are complete flowcharts or something like that in PowerPoint: Please note that I don't have a complete flow chart or something like that, I am drawing manually by adding objects like the arrows! Thanks for any hint on this!

(I am PowerPoint 2007)