Question

@Will.H

Answer 1

Steve thought u had to go mate xD

Answer 2

i'll solve this using GeoGebra and send you back the pic okay?

Answer 3

just send me coordinates... or pic is fine

Answer 4

is that the polygon indicated in the question or is it the one you did?

Answer 5

thats the one for the question

Answer 6

them how come the center of dilation is (-7,-4) when that coordinate is not one of the polygon vertices!

Answer 7

idk... but i didnt make anything... thats the one that was in the question

Answer 8

@mathmate

Answer 9

you dont know?

Answer 10

i know all about dilations
never seen somthing like this

Answer 11

i'll try to solve it on GeoGebra 1 moment

Answer 12

wanna come back to it?

Answer 13

no am solving it

Answer 14

ok

Answer 15

okay
let's get back to it later

Answer 16

ok

Answer 17

ill make new question

Answer 18

i don't even deserve a medal tho

Answer 19

yes you do... ill give you a medal cause i have 2 or 3 assignment i need to do offline through kik

Answer 20

hmm a hiden purpose lol okay

Answer 21

@devonhoward15
Do you want to solve this problem graphically or by transformations?

Answer 22

Transformations

Answer 23

Lol. Am being intrusive XD sorry

Answer 24

@Will.H
All the same! We're just trying to help.
What if you take a look at what I posted here:
http://openstudy.com/study#/updates/582cf777e4b093340004c25f
It gives all the details of the transformation.

The idea is to translate point A(x,y) to A'(x-a, y-b) where (a,b) is the centre of dilation to give A''(x1,y1)
Do the dilation, and translate the A''(x1+a, y1+b).

The same procedure can be done using geogebra.

Answer 25

edited:
@Will.H
All the same! We're just trying to help.
What if you take a look at what I posted here:

http://openstudy.com/study#/updates/582cf777e4b093340004c25f

It gives all the details of the transformation.

The idea is to translate point A(x,y) to A'(x-a, y-b) where (a,b) is the centre of dilation.
Do the dilation to give A"(x1,y1), and translate the A" back to A'''(x1+a, y1+b).

The same procedure can be done using geogebra.

Answer 26

Okay sounds interesting
So if we say we have point A(3,2) want to have it dilated by scale factor 1/2
And the center of dilation ia (-2,-4)

Is this what I have to do
A'(4+2,2+4) A'(6,6) THATS IT?

Answer 27

@Will.H , I am not online too often, so perhaps you could help @devonhoward15 when he returns.

Answer 28

I did help him with 15 questions in the past 1hr XD. Bare w me. Is what I did above correct

Answer 29

Almost,
just A'(3--2,2--4)=A'(5,6), after dilation, A''(2.5,3), then return to original coord. system A'''(2.5-2,3-4)=A'''(1.5,-1)
Check this on geogebra if you want. I may have erred.

Answer 30

We forgot something. Shouldn't we also multiply the coordinates by the scale factor?

Answer 31

For example the original case on dilations is
(x,y) --> (kx,ky) Where k is the scale factor

Answer 32

Oops, I got the last step wrong.
A'''(2.5-2,3-4)=A'''(0.5,-1)
It looks good graphically.

Answer 33

Yep, that how we got A''(5/2,6/2)=A''(2.5,3).

Answer 34

Okay to review the steps.
If we have the point (x,y) have it under dilation with scale factor k and center of dilation (m,s)

1st to do is
(kx,ky) then (kx - m, ky - s)
Do we need to do something else!?

Answer 35

The first step is translate
(x,y)->(x-a, y-b)
then dilate
(x,y)->(kx,ky)
then return by translation
(x,y)->(x+a, y+b)

If we combine all three (composing),
we get
(x,y)->(k(x-a)+a, k(x-b)+b)
in a single step!

Answer 36

That's what I needed to have. The single step. Thanks Mathmale Xx

Answer 37

Oh mathmate * sorry am used to Mathmale

Answer 38

No problem! It happens quite often, and I won't blame anyone! lol

Answer 39

Lol u can blame Mathmale

Answer 40

No, I won't blame my twin! lol

Answer 41

Are you a professor as well?

Answer 42

No I am not. I didn't know he is.

Answer 43

Oh he is. What are you then if u dm asking XD. A teacher?

Answer 44

Sorry, gtg!

Answer 45

Okay. Thanks again

Answer 46

k, bye!