In our image above, we have rotated the triangle four times to get it back to the original position. If you were to place your thumb in a set position on the desk and move the paper football with your index finger, you would be rotating the football about the fixed point of your thumb. Think about it as a paper football on your desk. In this figure the point of rotation is labeled and that is the point about which the triangle will move. Now we've created a triangle to see what would happen to it if we rotated it. What are some observations you can make about the movement of this figure? In this particular figure, the geometric figure is reflected three times. Figure ABCDE is looking in the mirror at figure A'B'C'D'E. You know how you look in a mirror and the objects you see are backwards? That is exactly how reflection symmetry works. Reflection symmetry is where a figure is reflected over a particular 'line of reflection' and the reflected figure is a mirror image of the original.

Next we'll create another figure to use in our exploration of reflection. During this translation the figure stays in the same in the exact same position and it simply move along the line of translation. The diagonal line serves as our 'line of translation,' it tells us how far and in which direction we will move our figure. Translation essentially means to move from point A to point B. Once we are familiar with the various movements we will create our own Tessellation.įirst we'll create a geometric figure to translate using Geometer's Sketch Pad. In this unit we will explore properties of how different geometric figures move through translation, rotation and reflection. Once students have had the opportunity to explore the various properties of angles and triangles, they can apply their knowledge to look deeper into Transformational Geometry and more specifically, Tessellations.

Rotating tessellation