Students learn the definition of an inscribed angle, and that the measure of an inscribed angle is equal to 1/2 the measure of its intercepted arc. Students also learn the following theorems related to inscribed angles. If two inscribed angles intercept the same arc, then the angles are congruent. An angle inscribed in a semicircle is a right angle. If a quadrilateral is inscribed in a semicircle, then opposite angles are supplementary. The measure of an angle formed by a chord and its tangent is half the measure of the intercepted arc. Students are then asked to find the missing measures of arcs and angles in given circles using these theorems.