How to use similar triangles to measure the height of objects.
How to define arc length and how it is different from arc measure; how to calculate the length of an arc.
How to define a central angle and find the measure of its intercepted arc; how to describe the intercepted arcs of congruent chords.
How to use a protractor to measure an angle.
How to calculate the measure of an inscribed angle.
How to define a secant; how to find the length of various secants in circles.
How to classify a triangle based on its side lengths and angle measures.
How to find the measure of one angle in any equiangular or regular polygon.
How to find the sum of the exterior angles in a polygon and find the measure of one exterior angle in an equiangular polygon.