Track quiz
Eight ideas, eight checks. Use the table if you get stuck.
| Idea | Remember |
|---|---|
| Linear pair | Two angles that share a vertex and an arm, on opposite sides of it, with outer arms in a line, total 180°. Angles that total 180° are supplementary. |
| Converse | A claim turned around is a new claim. One drawing can end it. |
| Vertically opposite | Two linear pairs and one subtraction make the facing angles equal. |
| Parallel lines | Corresponding angles are equal. Alternate are equal. Co-interior total 180°. |
| Equal angles | Equal corresponding or alternate angles make the lines parallel. |
| Same line | Two lines parallel to a third line are parallel to each other. |
| Which fact | Start from parallel lines for angles. Start from equal angles for parallel lines. |
| When is it true | Always, only on parallel lines, or false as stated. |
Two angles sit on a straight line. One is 70°. What is the other?
Two lines cross. One angle is 45°. What is the angle facing it?
Two angles are 80° and 100°. They are drawn far apart. Are they a linear pair?
Two lines are parallel. A co-interior angle is 110°. What is the other one?
A transversal makes equal alternate angles. What follows?
l is parallel to m. n is parallel to m. What is true about l and n?
A question says "the two banks are parallel". What do you use that fact for?
Is "corresponding angles are equal" true for any two lines?
Next: Triangles – Congruence Theorems, where triangles are matched the same careful way.