1. In the picture below there are pairs of angles that are congruent, and pairs of angles that are supplementary. In your own words, describe where two pairs of congruent angles are located and describe where two pairs of supplementary angles are located.
2. Drag point B so that the lines move. What happens to the congruent/supplementary angles? Do they remain congruent/supplementary, or do they change?
3. Why do you think the angles in the "cross" at the bottom not follow the same pattern as the other two crosses?
4. In order for the relationships you described in question 1, what MUST be true?