Geometry · Parallel Lines & Angle Pairs
Corresponding Angles
HSG-CO.C.9
Definition
Angles in matching positions at two intersections of a transversal; congruent when the lines are parallel.
Examples
- 70 = 70 degrees for a pair of corresponding angles on parallel lines.
- The top-left angle at each intersection is a pair of corresponding angles.
Key rule
Corresponding angles are congruent only when the two lines are parallel.
Memory hook
Same position at each crossing.