Key to Geometry Answers 46 Detailed Description — Key to Geometry offers a non-intimidating way to prepare students for formal geometry as they do step-by-step constructions. Using only a pencil, compass, and straightedge, students begin by drawing lines, bisecting angles, and reproducing segments. Later they do sophisticated constructions involving over a dozen steps and ... more »are prompted to form their own generalizations. When they finish, students have been introduced to 134 geometric terms and are ready to tackle formal proofs Book 4: Perpendiculars, Book 5: Squares and Rectangles, Book 6: Angles. These are the answers and notes for Books 4-6 of the Key to Geometry Series.