vertical angle observation

Move points on the line to change angle measures. Record your observations regarding angle relationships. Which angles are congruent? Which angles are supplementary? Are angles every complementary? If so, when? If no, why not? What angle sums do you find? Give examples and sketch diagrams to back up your observations. Do not limit your observations to these questions.

This is a Java Applet created using GeoGebra from - it looks like you don't have Java installed, please go to

Submit observations at the end of the period.

Guest Johnson, October 2, 2011, Created with GeoGebra