Another tool that will do it but runs around $40 though deals can be found, is a Digital Angle Gauge like this one http://www.wixey.com/anglegauge/index.html. Measures accurately to 0.1 degree. If you have a woodworker friend who may have one you might be able to use it for your measurements. I have one which I use as pictured on the link above to set my table saw angle and other such things where angle 'setting' or 'knowing' are important.