How to prove that an angle inscribed in a semicircle is a right angle; how to solve for arcs and angles formed by a chord drawn to a point of tangency.
How to find the angle of inclination of a line.
How to compute the angle between two vectors.
How to define alternate interior angles and their special properties.
How to define alternate exterior angles and their special properties.
How to label an angle and how to differentiate between acute, right, obtuse, and straight angles.
How to find the sum of a geometric series.
How to find the sum of an arithmetic series.
How to define adjacent angles.
How to use the power reduction formulas to derive the half-angle formulas.
How to determine the relationship between the side inequalities and angle inequalities in a triangle.
How to define and identify vertical angles.
How to relate the sides of an angle bisected and the lengths of the opposite side.
How to derive two more cosine double-angle formulas.