Angle Bisectors and Solving for an Angle

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Taught by mrbrianmclogan
  • Currently 3.0/5 Stars.
5360 views | 1 rating
Part of video series
Meets NCTM Standards:
Errors in this video:

At about the 1:23 mark (and he continues the mistake further in the problem), the teacher writes 3x+8 on the board instead of 3x+9. The teacher does the rest of the work correctly, but because of this error, he gets the wrong answer. He should get x=23 and measure of angle LKM=156.

Lesson Summary:

In this lesson, we learn about angle bisectors and how to use them to solve for unknown angles. By understanding that bisecting an angle cuts it in half, we can use this knowledge to find missing angles by setting them equal to each other. Through practice problems, we see how to use supplementary angles and solve for x to find the measure of an angle. This lesson is a great introduction to using geometry to solve for unknowns.

Lesson Description:

Using angle bisectors and supplementary angles to solve for x

I show how to solve math problems online during live instruction in class. This is my way of providing free tutoring for the students in my class and for students anywhere in the world. Every video is a short clip that shows exactly how to solve math problems step by step. The problems are done in real time and in front of a regular classroom. These videos are intended to help you learn how to solve math problems, review how to solve a math problems, study for a test, or finish your homework. I post all of my videos on YouTube, but if you are looking for other ways to interact with me and my videos you can follow me on the following pages through My Blog, Twitter, or Facebook.

Questions answered by this video:
  • What does angle bisector mean?
  • How can I solve for an angle measure when I know I have an angle bisector?
  • How do I solve for the measure of the angle when I the angle measure I am given has a variable in it?
  • Staff Review

    • Currently 3.0/5 Stars.
    This lesson shows how to solve for an angle measure when you are given the angle measure with a variable in it, and you know that you have an angle bisector.