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OpenSessame
 2 years ago
Find the image of P(–2, –1) after two reflections; first Ry=5 and then Rx=1.
A. (–2, –1)
B. (–1, –6)
C. (4, –9)
D. (1, –5)
OpenSessame
 2 years ago
Find the image of P(–2, –1) after two reflections; first Ry=5 and then Rx=1. A. (–2, –1) B. (–1, –6) C. (4, –9) D. (1, –5)

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e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2So the Ry=5 and Rx=1 are the lines you need to reflect across?

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Those are the reflections

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2A reflection is usually over a line.... so I want to make sure that is the notation you are using.

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2http://www.mathopenref.com/reflect.html Like it says there, "A transformation where each point in a shape appears at an equal distance on the opposite side of a given line  the line of reflection. " So, start by just doing a rough sketch. Does not need to be exact, but you need to find where the dot and line would be and how far the line is from the dot. If you can do that with math, great! But a sketch can help.

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Okay, but i dont understand what i have to do...

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Well, it needs to be an equal distance from the line on the other side of the line.

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Where did the line come from????

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Ry=5 \(\leftarrow\) that is the line part.

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Let me show you an example.

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Okay...Just show me with this one

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2If I work this that is me giving you an answer. If I work an example you can follow the process and answer your own homework. Lets say I take this random dot: dw:1376455485961:dw And lets say I have Ry=1, so the line where every Y is 1.

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2dw:1376455572591:dw

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Well, im really lost man...So i wouldnt even get it

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0That is an example already, im just doing a text review for before i take it. so it doesnt count

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2The important measure is the distance from the dot to the line. dw:1376455620753:dw Because I need to put the reflection the SAME DISTANCE on the other side of the line.

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2dw:1376455677255:dw

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Do the distance is the number in the equation?

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Let me try to do mine...one sec

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2The distance is the measure from your point and the line.

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Yours is done twice.... so see what you get for the first step and I can check it. Then the second step.

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0dw:1376455841757:dw

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2OK, that is a good (2,1).

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0dw:1376455914360:dw

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Now what do i do exactly?

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2OK, so what is the measure of the distance between your dot and the line? dw:1376456012468:dw

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Not quite. Tewo problems. This is change in y, not x, and distance is always positive.

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Yes. So your point is 4 above the line. That means the reflection must be 4 BELOW the line!

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2The line is at 5. So 4 below 5.... or 54=?

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Above is +, below is . Similarly, to the left of is , to the right of is +. Has to do with the Cartesian (xy) plane rules.

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Yes. That means the X is the same and the Y is now 9. So, the point after 1 translation is at (2,9). dw:1376456612998:dw

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Now you have the line Rx=1 to do the second reflection over.

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0dw:1376456678313:dw

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0dw:1376456695550:dw

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2So, how far this time?

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2\(\large\ddot\smile\)

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0so the point would me three to the right?

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Yes, 3 to the right of 1. And yep, that is it. (4,9).

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0wait im gonna see if it matches...

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Now, once you get good at the math, you should not need a sketch, but if yuou are ever in doubt, the rough sketch is there to help!

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Okay, the textbook just didnt really explain it

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2The thing I think most people mes up here is the line.... because x=0 is the y axis, and y=0 is the x axis. So they give you a y line but you draw it the same way as the x axis and that can be confusing!

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0yea, thats the right answer! thanks:)

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Can you help with some other questions that i dont get?

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Probably. I can explain it the same basic way I always do and hopefully it works like this and you get it!

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0What composition of rigid motions and a dilation maps EFGH to the dashed figure? https://study.ashworthcollege.edu/access/content/group/45b8c516100846d7aa1dbb9b62c786ff/geometry_exam_9_files/mc0201.jpg

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2OK. Dilation is going to be the size change. The rigit motion will get it from one place to the other.

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2It is probably easiest to do the dilation first. That will be some multiplication number. It is a ratio of the sides.

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2For example, this would be a dialation by 3..... dw:1376457753408:dw So start by finding how long the sides of both rectangles are.

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0wait is the answer D2*T<0,6>

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.22x the size, so yah, a dialation of 2. I didn't do the rest yet, but that would probably do it.

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Really??? woooohoooo

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Hmmm.... 6.... is that enough on the translation?

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Well, lets look at this real quick: dw:1376458028692:dw Now you need to double the size.

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0The dialation is times 2?

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2dw:1376458060944:dw OK, that makes them reflections of each other.

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2So now, one of two things needs to happne.... It either needs to be reflected over the x axis, OR, corner H needs to go all the way down to the bottom corner. dw:1376458143764:dw

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0so its shifted down 6

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Well, is that 6? That bottom corner is at 9....

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2or 10, actually.... counted wrong.

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2So it has to go from 2 above to 10 below... so....

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0so uhm...It would be 11?

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Yep! So 2D, T\(\langle 0,12\rangle\) is more like it.

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0that isnt one of my options

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Hmmm.... AH.... OK... the dialaion is probably also changing the translation! \(2\langle 0,6\rangle = \langle 0,12\rangle\)

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2So my bad. Looks like you did have it right.

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0YUS:) thanks though!

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0The hexagon GIKMPR and FJN are regular. The dashed line segments form 30° angles. What is r(240drg,0)(G)

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Well, the good news is you should understand the why a bit better! By exploring these, it lets you understand the why of it all....

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Hmmm..... I have not seen that form of question.... my geometry was a while back, and they have changed some of the things they do... Do you know what it is looking for, any terms? An angle?

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Thats really all i understand...

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2r is usually a radius.... but there is no distance....

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0I think r is the point?

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Thats the problem..

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2hmmm..... Well, 240/30=8 segments.

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0so 8 to the left or right?

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Well, if r is right... but that would be a guess on my part. Right 8 of G? I would need to see the reference to know they type of peoblem to get this one.

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0So would it be K???

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2I would only be guessing without the book and chapter.

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Okay...Well for me thats better then nothing!

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0The vertices of a triangle are P(–8, 6), Q(1, –3), and R(–6, –3). Name the vertices of \[R _{y=x}(PQR)\]

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Is that a reflection over the y axis?

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2AH HA! Found a reference! http://www.regentsprep.org/Regents/math/geometry/GT6/composition.htm

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2The composition part does not matter here.... the \(R_y\) part is reflection over the y axis!

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0So just make it the other sign?

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2And even better! http://www.regentsprep.org/Regents/math/geometry/GT5/reviewTranformations.htm

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Would the first point be (6,8)

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0OHHHH!!! MAKES SENSE!

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Amazing what finding a reference to the symbols can do!

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0YEA! Thanks so much man!

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0Write a sequence of rigid motions that maps ab and xy

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0LAST ONE AND I WILL UNDERSTAND GEOMETRY!

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2That composition part also confirms what we talked about with the <0,6> becoming <0,12>. The SECOND part of the compositon happens first!

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0the second part is (AB=XY)

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Are those seperate calculations for those two?

OpenSessame
 2 years ago
Best ResponseYou've already chosen the best response.0The top doesnt matter just look at the lines

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Yah, well, then that is some sort of what? Rotation, reflection etc?

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Remember that A is going to X and B is going to Y..... should be a huge clue.... YES! Some sort of reflection.

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2So, you just need to find the line they are reflected over.

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2It would be half way between them.

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Are they both the same distance from x=0?

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Did you count the distance from 0 to X and 0 to A?

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2Take a second look.... they are not the same.

e.mccormick
 2 years ago
Best ResponseYou've already chosen the best response.2You want the line half way between. So take the distance between the two points and divide by 2. It will be that far to the left of the right most line, and right of the left most line.
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