Angles in Parallel Lines Flashcards

All 6 cards in this deck

What is true about corresponding angles on parallel lines?

They are equal.

They are in the same position at each parallel line (an "F" shape).

What is true about alternate angles on parallel lines?

They are equal.

They lie on opposite sides of the transversal, between the parallel lines (a "Z" shape).

What is true about co-interior angles on parallel lines?

They add up to $180^\circ$.

e.g. if one is $110^\circ$, the other is $70^\circ$.

True or false? Co-interior angles on parallel lines are equal.

False. Co-interior angles sum to $180^\circ$; it is alternate and corresponding angles that are equal.

True or false? Alternate and corresponding angle facts only hold when the two lines crossed by the transversal are parallel.

True. Without parallel lines these angles need not be equal.

In a question saying "give a reason for each stage of your working", what must you write next to each angle you find?

The angle fact used, in standard wording.

e.g. "alternate angles are equal", "angles on a straight line sum to $180^\circ$", "angles in a triangle sum to $180^\circ$".