Use the protractor to find the measure of the angle: https://cdn.lti.glynlyon.com/interactives/chm/cdn_harness/cdn_harness.html?base=global&file=dla_protractor/js/protractor.js&dataBasePath=014e4175-daf1-4e3c-be4d-f952523a8c48&dlaFile=prt_mat07u08c01l01d.dla
Click once to pick up the protractor. Use your mouse to move it until it lines up correctly over the angle. Click again to lock the protractor into place.