Smart Protractor is in the 1st set of the Smart Tools collection.This app measures the angle and the slope of an object. It has three protractor modes.1. Touch mode : for angle. After putting an object on the screen, touch the screen.2. Plumb mode : for slope. A weight shows the slope of your device.3. Camera mode : goniometer, inclinometer. It uses camera view.* Main features:- Tilt units (degree, percent, radian)- Zero calibration- Orientation sensor on/off- Material design* Pro version added features:- No ads- Various Tilt units- Screen capture- Ruler, Level, Thread pitch* Do you want more tools?download [Smart Ruler Pro] and [Smart Tools] package.For more information, watch YouTube and visit the blog. Thank you.