Geometry · Points, Lines & Angles
Congruent Angles
HSG-CO.A.1
Definition
Angles that have equal measure, indicated by matching arc marks.
Examples
- If angle 1 = angle 2, the angles are congruent, shown with matching arc marks.
- Two 50 degree angles are congruent because they have equal measure.
Key rule
Matching arc marks on a diagram show which angles are congruent.
Memory hook
Same measure, matching arc marks.