Measures 2 is a handy application with a Protractor, Ruler, Spirit Level, Surface Level, Seismometer, Flashlight, and more tools.
https://mega.nz/#!DJV1zDpQ!RoSQlbAfLpNeIsBp2nSlGD36WUd5IzgPzcT1kpdqxGw
https://mega.nz/#!DJV1zDpQ!RoSQlbAfLpNeIsBp2nSlGD36WUd5IzgPzcT1kpdqxGw