Geometry introduces the tools central to the study of space and spatial relationships. This course begins with the development of the tools of geometry, including transformations, proof, and constructions. These tools are used throughout the course as students formalize geometric concepts studied in earlier courses, and extend those ideas to new concepts presented in the high school standards. Students begin to formalize geometric relationships involving angles, lines, triangles, quadrilaterals, and circles. Geometry provides students with an introduction to formal mathematical reasoning, logic, and proofs. Students are also introduced to what constitutes the standards of evidence in modern mathematics. Students spend time creating viable arguments around triangle congruence and similarity. They also use transformations as the key underlying definition of congruence and similarity. Students create arguments and solve problems with shapes represented both on and off the coordinate grid. Throughout the course, students focus on developing logical arguments and using geometry to model their world.