Parallel Lines Cut by a Transversal
Lines a and b are parallel and are intersected by a transversal c.
Drag the blue points on line c to move the transversal.
Important:
Make sure the blue points stay outside the parallel lines. If they fall between lines a and b, the angles will disappear.
Work in pairs to answer the following questions:
- How does moving the transversal affect the angles formed at its intersections with lines a and b?
- Which pairs of angles are always congruent?
- Which pairs of angles are always supplementary?