Videos

Rotations

Added Sep 19, 2016 •

Copy this URL:
Embed code:	<iframe class="edlio-embed-player" type="text/html" width="640" height="360" src="//talbert.fvsd.us/apps/embed/?v=120811" frameborder="0" allowfullscreen></iframe> Change dimensions

Show Transcript

alright let's talk today about  rotations in Geometry we have these when's called transformations in the third of our major types of Transformations is what we call a rotation and a rotation is just sickly when something turns or spins or something like that so rotations we know translations is when someone just kids are Glides or moves or shift and a reflection is when something has a mirror image of it a rotation no is like I said when something turns or rotates or spins what am I going to notice is that sometimes Reflections and rotations look similar but they don't look back to the same I think you can see that look at the images of those two red apples notice they don't look exactly the same on a rotation it's not going to be a mirror image it's not going to be symmetrical the bite mark out of that Apple isn't a symmetrical mirror image of the one it's a spun around version of the preimage  and  you can also tell by the direction that little leaf is facing which one is a reflection and which one is it rotation so that's what we see when we see a rotation oh my gosh what in the who is it okay I guess that guy likes to eat apples well okay as long as this guy's here and hanging around what's rotate him  alright what you need to know about rotations is it we can measure them  sometimes things can spin or turn a lot and sometimes they can spinner turn just a little bit if something does like a quarter-turn we would call that a 90 degree rotation what moves clockwise we would say it's a 90 degree clockwise rotation so remember clockwise vs. counterclockwise clockwise just means which way did hands on a clock though they go that way so that's clockwise can you spin this image 90 degrees counter sure this would be a counterclockwise 90° rotation okay each one of those are like it order of a turn because 90° is like a quarter of a turn could you do a full turn 180° that would be 180 degree rotation by the way if you go 180 degrees it doesn't really matter if you go clockwise or counterclockwise cuz you'll end up in the same spot these are all what we call angles of rotation and depending on how much or how little the angle is that tells how much the preimage is going to rotate to turn into a new image so you can also do a smaller angle of rotation like 30 what a larger one like 200 degrees  the most of the rotations that we're going to do our kind of common numbers Lake 90 degrees which is a quarter-turn or 180 degrees which is a half turn if you did a half turn and a quarter of a turn it went three quarters of the way around that would be what we call a 270 degree rotation by the way all three of these rotations are clockwise no these are kind of your most common rotations you could also do a half of a half turn which it are sorry a half of quarter turn which is like a 1/8 of a full turn and I would be 45 degrees  alright pretty simple now the kinds of problems that you're going do when you do rotations are going to be like this you might have to rotate this shape know when you rotate this every  point is going to rotate so if it was in quadrant 2 now it's going to be in quadrant and if you go on another 90 degrees and it's going to be down there in Quadrant 4 and then if you do another 90 degrees it's going to be in quadrant 3 and you could do a full circle 360 degree rotation and you'd be right back where you started if we wanted to rotate that whole shape it would be different and the whole shape would spin around each time  for instance if you had a point like this point point at -2, 4 and you wanted to where would that point end up if you rotated this thing 90 degrees clockwise just picture the whole graph rotating 90 degrees okay each quadrant would move clockwise right so it would be like that so where would that point end up it would end up exactly where you see it right now but  right there so this would be our a prime if we did a 90° clockwise okay what if you did point a and you wanted to go 180 degrees but you wanted to go counter-clockwise again can we just pictures this would be like going from that quadrant all the way down into the other quadrant down there counterclockwise sure alright so see what would happen if we turn the whole graph 180 degrees counterclockwise it be like that and so that would be where you're a prime would be when you move the graph back  that's not too bad right what's going to really make this easier is when you do this on your own if you actually will you move your page and turn your page or spin it around it'll really help you see where these rotations and up pretty much all we need to say except sometimes you're going to have to identify the number of degrees so on this one you can notice it goes from that quadrant to that quadrant did that quadrant which would be to 90 degree rotation so it would be a total of the 180 degree rotation pretty easy right all right that's all got to do so hope that all made sense and we will work on this some more in class  see you next time

Uploaded by Jeff Marbut.

Videos

Rotations

More videos from Jeff Marbut