What's a real good basic, high school or college geometry textbook? I have Coxeter's geometry, and it's very good, but he assumes too much sometimes for the very ignorant, such as myself. For example, he assumes the reader knows that any triangle with 2 endpoints in a semi-circle is a right triangle. I didn't know that so I found a proof online. But is their a book that stands above the rest in covering such elementary material?