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# Geometry HELP!

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Graph the image of the figure after a dilation with a scale factor of 1/3 centered at (1, −2).

The points of the figure/triangle are... (-8,-2), (-8, 4), and (4, 7).

someone plz help me understand this and teach me.

Thank you so much in advance!

Nov 29, 2017

#1
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Hi,

I have tried to show you with this sketch.

I have found the new point for just one of the vertices, you should be able to work our where the other two points go.

If you have any questions you can ask :)

Nov 29, 2017
#2
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The new coordinates are  given by :

[Vertex of triangle  - Center of Dilation  ] * (scale factor) + Center of Dilation

So we have

[ ( -8, - 2 )  - ( 1, - 2 ) ] (1/3)  +  ( 1, -2 )  =

[   ( -9, 0 ) ] (1/3) +  ( 1, - 2 )     =

( -3, 0 )  +  (1, - 2 )   =    ( -2, -2 )

[ ( -8, 4 ) - ( 1, - 2 ) ] (1/3)  + (1, - 2)   =

[ ( -9, 6) ] (1/3)  + ( 1, - 2 )  =

( -3, 2 )  +  ( 1, -2 )  =    ( -2, 0 )

[ ( 4, 7 )  -  ( 1, - 2 )  ] (1/3)   +  ( 1 , -2 )   =

[  ( 3 , 9 ) ] (1/3)  +  (1, - 2 )   =

( 1 , 3 )  +  ( 1, - 2 )  =  (2, 1)

Here are the pre and post images of the coordinates :

https://www.desmos.com/calculator/jahlfxvluy

Nov 29, 2017
edited by CPhill  Nov 29, 2017
#3
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Never mind

Melody  Nov 29, 2017
edited by Melody  Nov 29, 2017
edited by Melody  Nov 29, 2017