This document discusses inscribed angles and theorems related to them. An inscribed angle is an angle whose vertex is on a circle and whose sides are chords of the circle. The intercepted arc is the arc created by the chords of the inscribed angle. Three theorems are presented: if two inscribed angles intercept congruent arcs, the angles are congruent; if an inscribed angle intercepts a semicircle, the angle is a right angle; and if a quadrilateral is inscribed in a circle, its opposite angles are supplementary. The lesson plan is to introduce inscribed angles and develop theorems about them over two class periods with notes, examples, and a quiz.