Exploring parallelogram properties
1) Explore the properties of a parallelogram by dragging vertices A, B or C. What do you notice about its angles, diagonals, symmetry, and sides? Does it have a circumcircle or incircle?
2) Write down your conjectures in relation to your observations in 1); then check your conjectures by completing this Parallelogram Properties Quiz which will open in a new browser window. Continue until you get your % score and you are told you've completed the exercise. If you do not get 100%, repeat your dynamic exploration in 1) above.
3) Explain (prove) using the symmetry of the parallelogram why your conjectures are true. After writing your explanations down, check and compare them with those in this exercise Parallelogram Properties Explanations.
Michael de Villiers, 1 October 2011.