In this lesson our instructor talks about angles and arc. First she talks about central angle, sum of central angles, and arcs. Second, she discusses arc measure, arc addition postulate and arc length. Finally, she lectures on concentric circles and congruent circles and arcs. Four extra example videos round up this lesson.
Central angle: An angle whose vertex is at the center of a circle
The sum of the measures of the central angles of a circle all adjacent to each other is 360 degrees
Know the difference between a minor and major arc
Arc measure: The measure of a minor arc is the measure of its central angle. The measure of a major arc is 360 degrees minus the measure of its central angle
The measure of a semicircle is 180 degrees
Arc Addition Postulate: The measures of an arc formed by two adjacent arcs is the sum of the measures of the two arcs
Arc Length: A part of the circumference proportional to the measure of the arc compared to the entire circle
Concentric Circles: Circles that lie in the same plane with the same center, but have different radii
Concentric circles, along with all other circles, are similar
Circles that have the same radii are congruent
Congruent circles are also similar circles
Two arcs of one circle with the same measure are congruent arcs
Congruent arcs also have the same arc length
Angles and Arc
Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.