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Triangle ABC has vertices A(0,0), B(2,2), and C(5,-1). Find the coordinates of L, the midpoint of line segment AC, and M, the midpoint of line segment BC. Verify that line segment LM is parallel to line segment AB and LM= 1/2AB.

 Nov 24, 2015
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Midpoint of AC =  [ (5 + 0) / 2 , (-1 + 00 / 2 ]   =  [5/2, -1/2]   =  L

 

Midpoint of BC = [ ( 2 + 5) / 2 ,  (-1 + 2) / 2  ]   =  [7/2, 1/2]   = M

 

Slope of AB   =   [2 - 0] / [ 2 - 0]  = 2/2 =  1

 

Slope  of LM  =  [ -1/2 - 1/2] / [ 5/2 - 7/2]   =  [-1] /  [ - 2/2]  =  -1 / 1   = 1

 

So....LM is parallel to AB

 

And  the length of AB  =   sqrt(8)  =  2sqrt(2)

 

And the length of LM = sqrt [ 7/2  - 5/2)^2  +  ( 1/2 + 1/2)^2 ]   =  sqrt  [  1^2 +  1^2]   =   =  sqrt(2)  = (1/2)2sqrt(2)

 

 

 

 

cool cool cool 

 Nov 24, 2015

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