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A triangle with vertices A(-2,-1),B(-1,4)and C(5,0) is rotated 90 ̊ counter clockwise about vertex B. Find the Co-ordinates of the image of vertex X

 Feb 21, 2021
 #1
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For  ease, move B to the origin

Then A  becomes  ( -2 + 1 , -1  -4)  =  ( -1 , -5)

 

The 90°  counterclock-wise rotation rule  is   x , y  →    -y  , x

So the new point for  the provisional  "A"   becomes  (5, -1)

And A'  becomes   (5 - 1, -1 + 4)  =  (4, 3)

 

Likewise... C  becomes  ( 5 + 1,  0 -4)  =  (6,-4)

And the new point for provisional "B"  becomes  (4, 6)

And C' becomes  ( 4 -1, , 6 + 4)  =  ( 3 , 9)

 

 

 

cool cool cool

 Feb 21, 2021

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