Видео ютуба по тегу How To Construct 30 Degree Angle With Compass
How to Construct an Angle of 15°,30°,45°,60°,75°,90°,105°,120°,135°,150°, 165°, 180° Degree | Part 1
Construction of angle of 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165 and 180 degree new