Having trouble with geometry? Do Pi, the Pythagorean Theorem, and angle calculations just make your head spin? Relax. With Head First 2D Geometry, you'll master everything from triangles, quads, and polygons to the time-saving secrets of similar and congruent angles and it will be quick, painless, and fun. Through entertaining stories and practical examples, you'll go beyond boring problems and actually use what you learn to make real-life decisions.