Students' first experience with transformations is likely to be with specific shapes like triangles, quadrilaterals, circles, and figures with symmetry. Exhibiting a sequence of transformations that shows that two generic line segments of the same length are congruent is a good way for students to begin thinking about transformations in greater generality.

In this activity, learners design unique tiles and make repeating patterns to create tessellations. This activity combines the creativity of an art project with the challenge of solving a puzzle. This lesson features three investigations, in which learners make tessellations by translating, rotating, and reflecting the patterns.

This lesson unit is intended to help you assess how students reason about geometry and, in particular, how well they are able to: use facts about the angle sum and exterior angles of triangles to calculate missing angles; apply angle theorems to parallel lines cut by a transversal; interpret geometrical diagrams using mathematical properties to identify similarity of triangles.

In this activity, learners slide shapes to create unusual tiled patterns. Learners transform a rectangle into a more interesting shape and then make a tessellation by repeating that shape over and over again. Learners will also calculate the area of a rectangle. This activity works best as a "centers" activity.

This lesson unit is intended to help you assess how well students are able to: interpret a situation and represent the variables mathematically; select appropriate mathematical methods; interpret and evaluate the data generated; and communicate their reasoning clearly.

This lesson unit is intended to help teachers assess how well students are able to: use the area of right triangles to deduce the areas of other shapes; use dissection methods for finding areas; organize an investigation systematically and collect data; deduce a generalizable method for finding lengths and areas (The Pythagorean Theorem.)

This lesson unit is intended to help teachers assess how well students are able to: recognize and visualize transformations of 2D shapes; and translate, reflect and rotate shapes, and combine these transformations. It also aims to encourage discussion on some common misconceptions about transformations.

In this video segment from Cyberchase, Harry uses tessellations to wallpaper his apartment. ***Access to Teacher's Domain content now requires free login to PBS Learning Media.