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Can the sides of a right triangle form a geometric series.

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jimb840 | Student, Grade 9 | Salutatorian

Posted September 30, 2013 at 2:44 PM via web

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Can the sides of a right triangle form a geometric series.

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted September 30, 2013 at 2:51 PM (Answer #1)

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Three consecutive terms of a geometric series a, b, c have a common ratio `b/a = c/b = r` .

If the three sides of a right triangle a, b, c form a geometric series, the length of the sides can be expressed as a, ar and ar^2.

The sides of the triangle follow the rule `a^2 + (ar)^2 = (ar^2)^2`

=> `1 + r^2 = r^4`

=> `r^4 - r^2 - 1 = 0`

Let `r^2 = x`

=> `x^2 - x - 1 = 0`

=> `x = (1 +- sqrt(1 + 4))/2 = (1 +- sqrt 5)/2`

For `x = (1 + sqrt 5)/2` , r is real.

It is possible to have three sides of a right triangle form a geometric series.

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