Lines carry over as lines of equal length, angles maintain their measure, and parallel lines remain parallel. Two-dimensional figures are congruent if one can be transformed into the other through rotations, reflections, and translations; the process showcasing this congruence should be stated. The transformations of dilations, translations, rotations, and reflections on coordinates are used to explain changes in two-dimensional figures.

A similar idea applies to figures being considered as similar if one can morph into the other by rotations, reflections, translations, and dilations, and the process should also be described. Informal arguments are used to proof facts relating to angles in triangles, angles created when parallel lines intersect, and the criteria for triangle similarity.

Explanations should be provided proving the Pythagorean Theorem and its converse. The theorem is used to find unknown lengths in right triangles in real-world and mathematical contexts, both two and three-dimensional, and also to calculate the distance between two points in a coordinate system. Knowledge and application of formulas for the volumes of cones, cylinders, and spheres is expected for resolving problems.