Grades 9-10 Video Solutions 2013-Level 9&10 Video Solutions 2013 problem9

Video Transcription

Question number nine, the three-quarter circle shown with center M and an orientation arrow over here is first rotated counterclockwise  by 90 degrees around M and then reflected about the X-axis. Which of the following shows the end result of these transformations?  So it's best to draw pictures in this case.  And what I have done is prepared three diagrams. The starting point here is labeled number one and then we need to rotate this counterclockwise. So in that direction, 90 degrees.  So what happens is the arrow ends up in quadrant three.  With the same orientation.  So we have a picture that kind of looks something like this.  And then what we're going to do is rotate that picture around the X-axis.  So we do a rotation like so and now the arrow ends up in quadrant two facing the opposite direction.  And so that looks like the diagram in D.

Video Summary

Question number nine, the three-quarter circle shown with center M and an orientation arrow over here is first rotated counterclockwise by 90 degrees around M and then reflected about the X-axis. Which of the following shows the end result of these transformations? So it's best to draw pictures in this case. And what I have done is prepared three diagrams. The starting point here is labeled number one and then we need to rotate this counterclockwise. So in that direction, 90 degrees. So what happens is the arrow ends up in quadrant three. With the same orientation. So we have a picture that kind of looks something like this. And then what we're going to do is rotate that picture around the X-axis. So we do a rotation like so and now the arrow ends up in quadrant two facing the opposite direction. And so that looks like the diagram in D.

Keywords

geometry

transformations

rotation

reflection

quadrants