Geometry · Triangles & Congruence
Triangle Angle Sum
HSG-CO.C.10
Definition
The interior angles of any triangle always add up to 180 degrees.
Examples
- 50 + 60 + 70 = 180 degrees.
- In an equilateral triangle, each angle is 60, so 60 + 60 + 60 = 180.
Key rule
The three interior angles of any triangle sum to exactly 180 degrees.
Memory hook
Every triangle's angles add to 180 degrees.