This two-minute video animation explains how to measure angles. An angle is two rays that share a common endpoint. the common point is called the vertex. You can use a protractor to measure angles. Acute angles are less than 90 degrees. Right angles ...are 90 degrees, and obtuse angles are greater than 90 degrees but less than 180 degrees. This video explains this and uses excellent graphics. (02:11)[more]

The instructor uses an electronic sketchpad to demonstrate how to constucut angles. Video discusses vocabulary and symbols associated with angles, ray (sides of the angle), vertex (the point where the rays start). It then goes on to use the protrac...tor to measure an angle. It starts with where to put one line of the angle and then where and what to measure. It also instructs students which set of numbers to use on a protractor. Then examples are measured. Good video for instruction and review for any grade level. (06:19)[more]

Students learn the definition of an angle and the concept of measure, including the following vocabulary: side, vertex, protractor, degrees, right angle, acute angle, obtuse angle, and straight angle. (02:26)

The instructor in this video demonstrates that an inscribed angle is half of a central angle that subtends the same arc. The instructor 'writes' using computer software. (14:16)

A teacher challenges students to apply their knowledge of triangles in this video. Students are given measurements of three possible sides of a triangle and are asked whether or not a triangle could be formed with the sides given. The teacher expla...ins each example and discusses why or why not the sides could form angles therefore forming a triangle. (02:58)[more]

This video uses an electronic black board with different-colored 'pens'. Using what we know about angles students need to figure out the measurement of the other angles in the figure that is drawn. The video should be paused then restarted for solu...tion. Narrator mentions that this is good practice for SAT’s. This could also be a challenge for high level middle school students. Good quality video. Good for middle elementary and middle school students. (09:01)[more]

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