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Хэрэв та вэб шүүлтүүртэй газар байгаа бол домэйн нэрийг *.kastatic.org and *.kasandbox.org блоклосон эсэхийг нягтална уу.

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Цаг: 0:00Нийт үргэлжлэх хугацаа:2:56

Video transcript

so I'm here on the Khan Academy exercise for mapping shapes and I'm asked to map the movable quadrilateral onto quadrilateral ABCD using rigid transformations so here in blue I have the movable quadrilateral and I want to I want to map it onto this quadrilateral in gray and we have a series of tools here rigid transformations of translation rotation or reflection on the Khan Academy tool and of course we can undo it so the technique I am going to use to do this is I'm gonna first use translation to make one of the corresponding points overlap with the point that corresponds to so for example it looks like this corresponds to point C right over here and so I'm going to translate and so notice once I click that I can translate this around so I'm going to translate right over here to point C and now let's see to make these two overlap I really can't do any more translation I made one point overlap do I rotate or do I reflect well if I I bought it right over here it looks like I am doing a rotation let me try to make use a rotation to make this segment right over here overlap with segment C D so let me do a rotation now and so let's see yep this is looking good there you go we did the rotation and we are done now let's do another example so here what do we need to do alright so I'm going to do the same technique this seems to correspond to Point C so I'm going to translate first so translate first and then there's something interesting going on right over here because I've actually been able to overlap Point C and a by shifting it by translating it I should say and so it's not clear if I were to rotate it then I would loot then I would lose the fact that a that the point that corresponds to a is now sitting on top of a and the point that corresponds to C is now sitting on top of C it feels like a reflection and it looks like a line that would actually contain the points a and C if we reflect over that line then we'll be in good shape so let me see a reflection so let me move the line see ya whoops and there that's not what I wanted to do so let's see let me move my line so that is I think a good line of reflection and then let me actually try to reflect and there you go I was able to reflect over that line and my clue that I had to reflect over the line that contained a and C is that the points a and C and their images after the transformation we're all sitting on top of each other so that was a good clue that on a reflection if if they're both sitting on the line of reflection that they wouldn't move so to speak and there you have it so this was a translation and then a reflection