This hands-on series for elementary and middle school teachers introduces geometric reasoning as a method for problem solving; deepens understanding of some important geometric ideas, such as symmetry, similarity, and trigonometry; and provides ideas for applying the concepts covered in the classroom. In the video programs, which are organized around the content standards of the National Council of Teachers of Mathematics (NCTM), workshop participants explore the properties of geometric figures, make constructions using pencil and paper or dynamic software, practice using mathematical language to express ideas and justify reasoning, and explore the basics of formal mathematical proofs and solid geometry.