After teaching students the lesson on right triangle Trigonometry, I take my students outside for this activity which is finding the height of the school flagpole by using right triangle trigonometry. My students make the Clinometers out of protractors, straws, string, and washers, then use them to find the angle of elevation from their line of sight to the top of the flagpole. This is a great hands on lesson that helps students understand what they are actually calculating in class!