Theorem 03 - Alternate Angles and Parallel Lines
- Author:
- SeamusMcCabe
- Topic:
- Angles
This theorem states that alternate angles are always equal when parallel lines are crossed by a transversal. If the alternate angles are equal then the lines must be parallel.
Notice that in the diagram on the left the alternate angles are different but in the diagram on the right the alternate angles are equal.
Change the diagram on the left to make the alternate angles equal.
What do you notice about the black lines?