How does DG teach construction with a straight edge and compass?
Right from the start (Chapter 0 Geometric Art) students use the ruler and compass to create geometric art. Then on an almost daily basis in Chapters One and Two students use the ruler, protractor, and compass to perform investigations to discover geometric properties (vertical angles and the properties of parallel lines). In Chapter Three we introduce the classic Euclidean compass and straightedge constructions. This is done inductively with students discovering the construction methods rather than the constructions being a set of rules or steps to memorize. The Euclidean constructions are blended with paper folding constructions (patty paper geometry) to reinforce the properties being discovered. We also recommend that teachers use The Geometer’s Sketchpad at this time as a third way to reinforce the concepts they are learning. The use of the compass and straightedge as tools for construction exercises as well as tools for discovery continue throughout the remainder of the text.
