# parallel lines and transversal

Author:
Mathguru
We can clearly see three lines. Two are blue and one is gray. We can change the position of these three lines with free points A, B, C, D and E. We can see that the gray line (transversal) intersects the two straight parallel lines (blue) and makes interior angles b, d, e and h and exterior angles a, c, f and g. In this situation 4 types of angles are formed. 1. Corresponding angles 2. Alternate interior angles 3. Alternate exterior angles 4. Interior angles on the same side of the transversal c and e, a and h, d and f and b and g are pairs of corresponding angles. d and h and b and e are alternate interior angles. c and g and a and f are alternate exterior angles. b and h and d and e are interior angles on the same side of the transversal. Move the free objects A, B, C, D and E and observe how the angles get changed.
Questions to think about 1. What is the relation between c and e, a and h, d and f and b and g (that is, between the pairs of corresponding angles)? 2. What is the relation between d and h and b and e (that is, alternate interior angles)? 3. What is the relation between c and g and a and f (that is, alternate exterior angles)? 4. What is the relation between b and h and d and e (that is, interior angles on the same side of the transversal)?