Question 221486: a(k,3) and b(1,5) are two points.
If /ab/= 4.472, find two values for k.
Answer by RAY100(1637)   (Show Source):
You can put this solution on YOUR website! Remember the distance formula, d = sqrt{ (y2-y1)^2 +(x2-x1)^2 }
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and |ab| = distance = 4.472
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4.472 = sqrt{ (5-3)^2 + (1-k)^2 },,,,,,square both sides
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4.472 ^2 = { (2)^2 + (1-k)^2 }
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4.472^2 -2^2 = (1-k)^2
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16 = 1-2k+k2
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0= -15 -2k +k^2 = k^2 -2k -15,,,,,factor
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(k-5)(k+3) = 0
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k=5,,,,-3
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check...(k,3) ,,,(1,5)
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(k=5),,,d= sqrt{ (2)^2 + (-4)^2 } = sqrt{ 4 +16} = sqrt20 = 4.472,,,ok
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(k=-3),,d= sqrt{ (2)^2 + (4)^2} =sqrt{4+16} = sqrt20 = 4.472,,,,,,ok
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