Geometry: Angle Relationships and Triangle Proofs

Vocabulary flashcards covering geometric properties of parallel lines, transversals, and triangle angle sum proofs based on the lecture worksheet.

Alternate Interior Angles

Angles located on opposite sides of a transversal line and between two parallel lines, which are congruent to each other.

Straight Angle Sum

The property stating that adjacent angles forming a straight line have measures that sum to $180^\circ$.

Triangle Angle-Sum Theorem

The theorem stating that the measures of the three interior angles of a triangle sum to $180^\circ$, represented as $x + y + z = 180^\circ$.

Supplementary Angles

Two angles whose measures add up to $180^\circ$.

Transversal

A line that intersects two or more parallel lines, creating pairs of congruent and supplementary angles.

Triangle Angle Proof Worksheet

A set of geometric proofs using parallel lines, alternate interior angles, and straight line properties to show that the angles of a triangle add up to $180^\circ$.