Explore! Parallel Lines Intersected by a Transversal
a and b are parallel lines. They are cut by transversal c. Drag the blue points on c to move the transversal. Note: Do not allow the blue points to fall inside the parallel lines or the angles will disappear!
Questions to Discuss: Which angles are always congruent? Note: Congruent means same shape (same angle measure) and same size. Which angles are vertical angles? Which angles are adjacent angles? Which angles are always supplementary? Think: What does supplementary mean? Move c to the right. How does this affect the angles formed by the intersection of a and b with c? Do they get bigger or smaller? Why? Move c to the left. How does this affect the angles formed by the intersection of a and be with c? Do they get bigger or smaller? Why? Do the bottom four angles stay the same as the top four angles? Why or Why not? Challenge!- Make an educated guess! What are alternate interior angles, alternate exterior angles, and corresponding angles? Think about what each word means and make a good guess!