![]() We can now move this point 5 right and then 2 up.įrom this point we need to draw a shape that is the same as shape A.Ī rotation turns a shape around a fixed point. We can start by picking a point on shape A. Means we need to move the shape 5 right and 2 up The transformation is a translation by the vector We can write 6 left and 5 up as a vector: We have a translation 6 to the left and 5 up. Next we look at how far to move in the up or down direction: We can now look at how far we need to move to get from the point on A to the same point on Bįirstly we look at the left or right direction: To find out how much the shape has moved we need to pick a point on shape A and find the same point on shape B. We put a set of brackets around these numbers.Ī movement to the right is positive and a movement to the left is negative.Ī movement up is positive and a movement down is negative. We write the left/right movement on top of the up/down movement. We can describe a translation using a vector. The transformation that maps shape A onto shape B is a translation 4 right and 3 up. Now we can look at how far up or down to move. We start by looking at how far to move left or right. If we take the bottom right corner of A we have to see how far we have to move the to get to the bottom right corner of B. We need to know how far to move left/right and how far to move up/down. We can take any point of shape A and see how far we have to move to get to the same point on shape B. We also need to know by how much the shape has moved. This transformation is called a translation We can see that the shape has moved and all points have moved by the same amount. All points of the shape must be moved by the same amount.Ī translation can be up or down and left or right.Įxample: Describe the transformation that maps shape A onto shape B And so this would be negative 90 degrees, definitely feel good about that.A translation moves a shape. And this looks like a right angle, definitely more like a rightĪngle than a 60-degree angle. And once again, we are moving clockwise, so it's a negative rotation. This is where D is, and this is where D-prime is. Point and feel good that that also meets that negative 90 degrees. This looks like a right angle, so I feel good about We are going clockwise, so it's going to be a negative rotation. Too close to, I'll use black, so we're going from B toī-prime right over here. Let me do a new color here, just 'cause this color is Much did I have to rotate it? I could do B to B-prime, although this might beĪ little bit too close. I can take some initial pointĪnd then look at its image and think about, well, how I don't have a coordinate plane here, but it's the same notion. Well, I'm gonna tackle this the same way. So once again, pause this video, and see if you can figure it out. So we are told quadrilateral A-prime, B-prime, C-prime,ĭ-prime, in red here, is the image of quadrilateralĪBCD, in blue here, under rotation about point Q. So just looking at A toĪ-prime makes me feel good that this was a 60-degree rotation. And if you do that with any of the points, you would see a similar thing. Another way to thinkĪbout is that 60 degrees is 1/3 of 180 degrees, which this also looks Like 2/3 of a right angle, so I'll go with 60 degrees. One, 60 degrees wouldīe 2/3 of a right angle, while 30 degrees wouldīe 1/3 of a right angle. This 30 degrees or 60 degrees? And there's a bunch of ways The counterclockwise direction, so it's going to have a positive angle. And where does it get rotated to? Well, it gets rotated to right over here. Remember we're rotating about the origin. Points have to be rotated to go from A to A-prime, or B to B-prime, or from C to C-prime? So let's just start with A. ![]() So I'm just gonna think about how did each of these So like always, pause this video, see if you can figure it out. ![]() ![]() We're told that triangle A-prime, B-prime, C-prime, so that's this red triangle over here, is the image of triangle ABC, so that's this blue triangle here, under rotation about the origin, so we're rotating about the origin here.
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