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.