This book contains a new and much easier system to use for the calculation of trigonometry problems occurring in the school, office, and workplace. Included are several trigonometry aids, which greatly simplify the calculation of triangles. There is also an explanation in minute detail of the production methods used in the engineering industry, including all the trigonometry calculations required prior to the precision manufacture of sheet metal, screw-cut, milled, drilled, and turned components. The fifty explanatory drawings explain how one can discover by calculation all the drawing’s unknown dimensions required for the production of precision components.