# Explore Isosceles Trapezoid Properties

- Author:
- Tammy Jones, kjmillikan

- Topic:
- Trapezoid

Click on Show Side Lengths, select point A or B and move it around.
1. What do you notice is always true about the side lengths?
Hide the side lengths, and click on Corner Angle Measures. Now move around point A or B again.
2. List any pairs of congruent angles or supplementary angles. Do these pairs always stay supp or congruent?
Hide the angle measures, now show the slopes. Again Move around point A or B.
3. What is always true about the slopes?
4. What can you infer because of the answer to question 3?
Hide the slopes, and click on the "Show Lengths of AE, BE, CE, DE" and move point A or B again.
5. What do you notice is always true about these lengths?
Hide the lengths, and now click on "and Lengths" next to diagonals, and move around A or B.
6. What do you notice is always true about the diagonals.
Hide the lengths, finally select "other angle measures", move points A or B.
7. List all pairs of congruent angles you see.
8. Label the angles you listed in question 7 with the following angle relationships: Vertical Angles, Alternate Interior Angles, Interior Angles on the Same Side/ Supplementary.
9. Using the picture, and your answers to this exercise, what are the properties of Isosceles Trapezoids that are always true?
10. Figure FGIH is not and Isosceles Trapezoid. It is jsut a trapezoid. What properties from your answer to question 9 still remain true? What properties no longer apply?