**Videos**

(11:12) Circle Notation

(4:58) Length of an arc that subtends a central angle

(2:18) Finding central angle measure given arc length

(14:16) Inscribed and central angles

(6:57) Perpendicular radius bisects chord

(5:35) Right triangles inscribed in circles

(11:39) Area of inscribed equilateral triangle (some basic trig used)