Learning geometry doesn't have to hurt. With a little bit of friendly guidance, it can even be fun! Geometry For Dummies, 2 nd Edition , helps you make friends with lines, angles, theorems, and postulates. It eases you into all the principles and formulas you need to analyze two- and three-dimensional shapes, and it gives you the skills and strategies you need to write geometry proofs. Before you know it, you'll be understanding proofs like an expert. You'll find out how a proof's chain of logic works and discover some basic secrets for getting past rough spots. Soon, you'll be proving triangles congruent, calculating circumferences, using formulas, and serving up pi. The non-proof parts of the book contain helpful formulas and tips that you can use anytime you need to shape up your knowledge of shapes. You'll even get a feel for why geometry continues to draw people to careers in art, engineering, carpentry, robotics, physics, and computer animation, among others. You'll discover how to: Identify lines, angles, and planes Measure segments and angles Calculate the area of a triangle Use tips and strategies to make proofs easier Figure the volume and surface area of a pyramid Bisect angles and construct perpendicular lines Work with 3-D shapes Work with figures in the x-y coordinate system So quit scratching your head. Geometry For Dummies, 2 nd Edition, gets you un-stumped in a hurry. When you need to shape up, open up the included Geometry Workbook For Dummies , which contains over 290 pages with hundreds of practice problems featuring ample workspace to work out the problems. Each problem includes a step-by-step answer set to identify where you went wrong (or right). You'll be proving yourself proof-worthy in no time! AUTHOR BIO: Mark Ryan owns and operates The Math Center in Chicago, a teaching and tutoring service for all math subjects as well as test preparation. He also wrote Geometry Workbook For Dummies .