Yes, the geometry textbook by Harold Jacobs, and our videos that go along with it, is Euclidian Geometry – it does contain proofs. Some parents are under the misconception that is does NOT contain proofs since Harold use less of the formal 2 column proof methodology in his 3rd edition.
Here is an email we received from Harold when we asked him to clarify:
“I endeavored in the third edition to build the exercises around more profound material and to give the student more freedom in developing proofs. For really challenging problems, this meant leading the student along in a Polya-like style. Forced into two-column format, some of the proofs in this edition would run 15-20 steps, much longer than the typical 4- or 5-step proofs in the earlier edition. In his foreword on page xii of the book, Andrew Gleason of Harvard University wrote that ‘This book restores the idea of proof to its rightful place in geometry. Whoever studies this text will know what a proof is, what has been proved, and what has not.’ He, together with Dr. Peter Renz, who wrote the supplemental notes in the Teacher’s Guide, looked carefully at the content and structure of all of the exercises and gave his full approval. I feel very honored that he would take so much of his time to do this. Gleason, by the way, is a former president of the American Mathematical Society and one of our country’s most prestigious mathematicians. I hope this helps clarify what has changed between the second and third editions as well as why.”
What does this mean? This geometry course is not like the geometry I had in high school – BORING. Most geometry textbooks (courses) spend so much time in the middle of proofs that the student forgets that they are doing geometry and learn to hate the material. Jacobs has treated proof in a way that is engaging and based on real world geometric systems.