x^2 + 12^2 = (3x)^2 → x^2 + 144 = 9*x^2 → 8*x^2 = 144 → x^2 = 18 → x = √¯¯18 = 3√¯¯2 ≈ 4.243
So the triangle's sides are 3√¯¯2 , 12, 9√¯¯2.
2006-09-18 16:35:19
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answer #1
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answered by Arash 3
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This answer uses as much algebra as possible, instead of arithmetic.
x^2 + 12^2 = (3x)^2?
Distributive Property on the right side:
x^2 + 12^2 = 3^2 * x^2
12^2 = 3^2 * x^2 - x^2
Distributive Property again:
12^2 = x^2 ( 3^2 - 1 )
x^2 = 12^2 / (3^2 - 1)
x =+/- sqrt(12^2 / (3^2 - 1) )
x =+/- 12 / sqrt( 3^2 - 1 )
Difference of two squares
x =+/- 12 / sqrt ( (3+1) * (3-1) )
x =+/- 12 / sqrt ( (4) * (3-1) )
x =+/- 12 / (2 * sqrt (3-1) )
x =+/- 6 / sqrt (3-1)
x =+/- 6 / sqrt (2)
x =+/- 6 / (2 ^ 1/2)
Multiply numerator and the denominator by the denominator
x =+/- ( 6 (2 ^ 1/2) ) / (2 ^ 1/2) ^ 2
x =+/- ( 6 (2 ^ 1/2) ) / 2
x =+/- 3 (2 ^ 1/2)
Very simple using only algebra, in only 15 steps.
2006-09-18 17:48:50
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answer #2
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answered by sexy 2
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It's not hard:
x squared + 144 = 9x squared
144 = 8x squared
18 = x squared
x = 18 to the half power or -18 to the half power
x = 3 square roots of 2 or -3 square roots of 2
2006-09-18 16:33:21
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answer #3
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answered by Anonymous
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take x^2 to the right
12^2 = (3x)^2-x^2 = 8x^2
devide my 8 on both sides
x^2 = 12^2/8 = 144/8 = 18 = (3*sqrt(2))^2
take square root x = 3 sqrt(2) or - 3sqrt(2)
2006-09-18 16:27:09
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answer #4
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answered by Mein Hoon Na 7
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Divide through by x^2:
1 + (12/x)^2 = 9
This means (12/x)^2 = 8, or 12/x = sqrt(8) = 2 sqrt(2). So x = 12/(2 sqrt (2)) = 3 sqrt(2). If you require integer solutions, there are none.
2006-09-18 16:32:29
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answer #5
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answered by alnitaka 4
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x=3*2^(1/2)
2006-09-18 16:30:00
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answer #6
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answered by sharanan 2
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assuming nothing it mistyped
x^2 + 12^2 = (3x)^2
x^2 + 144 = (3x)^2
x^2 + 144 = 9x^2
8x^2 + 144
x^2 = 18
x = sqrt(18)
x = -3sqrt(2) or 3sqrt(2)
the sides are 18, 12, and 54
2006-09-18 17:27:37
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answer #7
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answered by Sherman81 6
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x^2 + 144 = 9x^2 => 144 = 8x^2 => 18 = x^2 => x = 3sqrt (2).
2006-09-18 17:51:29
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answer #8
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answered by flyfisher_20750 3
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x^2 + 144 = 9x^2
144 = 8x^2
18 = x^2
x = 18^(1/2) or -18^(1/2)
x = 3sqrt(2) or -3sqrt(2)
2006-09-18 16:29:10
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answer #9
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answered by عبد الله (ドラゴン) 5
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x^2+144=9x^2
so 8x^2=144
x^2=18
x=sqrt(18)
2006-09-18 16:27:03
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answer #10
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answered by astrokid 4
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