Lines and Angles

Core Geometric Axioms

1. Linear Pair Axiom: If a ray stands on a line, the sum of two adjacent angles formed is $180^\circ$.
2. Vertically Opposite Angles Theorem: If two lines intersect, vertically opposite angles are equal.
3. Parallel Lines & Transversal: Corresponding angles are equal; Alternate interior angles are equal; Interior angles on the same side of transversal sum to $180^\circ$.