Today we're going to launch into a series of dynamic geometry activities. By using tools that reflect the underlying concepts of geometric figures, we'll develop a deeper understanding.
Geometer's Sketchpad RefresherComplete the following:  Launch Geometer's Sketchpad (GSP5)
 Draw a point, line, ray, and line segment
 Construct an angle and measure that angle.
Things to notice:  Notice how GSP simulates points, lines, rays, and segments
 Pay careful attention to how angles are named. The order of points listed describes where the vertex and legs of the angle are
 Notice how GSP will always measure the convex angle (less than 180º)
Investigation: Complementary and Supplementary AnglesDownload the GSP file here. Using the included sketch, identify pairs of angles that are...  Complementary: they add up to 90º
 Supplementary: they add up to 180º
