Get leg length depending on another leg knowing the perimeter of a rectangle triangle [closed]












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Knowing the perimeter of the triangle, how can i find the side (leg) b in function of the leg a and it's perimeter p.



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closed as off-topic by mrtaurho, Martin R, Leucippus, Shailesh, max_zorn Jan 20 at 3:43


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – mrtaurho, Martin R, Leucippus, Shailesh, max_zorn

If this question can be reworded to fit the rules in the help center, please edit the question.
















  • $begingroup$
    The hypotenuse has length $sqrt{a^2+b^2}$, by the Pythagorean identity. So we have that $a + b+sqrt{a^2+b} = 31$. We can now solve for $b$ in terms of $a$.
    $endgroup$
    – jordan_glen
    Jan 19 at 20:09
















-3












$begingroup$


Knowing the perimeter of the triangle, how can i find the side (leg) b in function of the leg a and it's perimeter p.



enter image description here










share|cite|improve this question











$endgroup$



closed as off-topic by mrtaurho, Martin R, Leucippus, Shailesh, max_zorn Jan 20 at 3:43


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – mrtaurho, Martin R, Leucippus, Shailesh, max_zorn

If this question can be reworded to fit the rules in the help center, please edit the question.
















  • $begingroup$
    The hypotenuse has length $sqrt{a^2+b^2}$, by the Pythagorean identity. So we have that $a + b+sqrt{a^2+b} = 31$. We can now solve for $b$ in terms of $a$.
    $endgroup$
    – jordan_glen
    Jan 19 at 20:09














-3












-3








-3





$begingroup$


Knowing the perimeter of the triangle, how can i find the side (leg) b in function of the leg a and it's perimeter p.



enter image description here










share|cite|improve this question











$endgroup$




Knowing the perimeter of the triangle, how can i find the side (leg) b in function of the leg a and it's perimeter p.



enter image description here







geometry trigonometry






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edited Jan 19 at 19:59









mrtaurho

5,59051440




5,59051440










asked Jan 19 at 19:58









DeFabregasDeFabregas

12




12




closed as off-topic by mrtaurho, Martin R, Leucippus, Shailesh, max_zorn Jan 20 at 3:43


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – mrtaurho, Martin R, Leucippus, Shailesh, max_zorn

If this question can be reworded to fit the rules in the help center, please edit the question.







closed as off-topic by mrtaurho, Martin R, Leucippus, Shailesh, max_zorn Jan 20 at 3:43


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – mrtaurho, Martin R, Leucippus, Shailesh, max_zorn

If this question can be reworded to fit the rules in the help center, please edit the question.












  • $begingroup$
    The hypotenuse has length $sqrt{a^2+b^2}$, by the Pythagorean identity. So we have that $a + b+sqrt{a^2+b} = 31$. We can now solve for $b$ in terms of $a$.
    $endgroup$
    – jordan_glen
    Jan 19 at 20:09


















  • $begingroup$
    The hypotenuse has length $sqrt{a^2+b^2}$, by the Pythagorean identity. So we have that $a + b+sqrt{a^2+b} = 31$. We can now solve for $b$ in terms of $a$.
    $endgroup$
    – jordan_glen
    Jan 19 at 20:09
















$begingroup$
The hypotenuse has length $sqrt{a^2+b^2}$, by the Pythagorean identity. So we have that $a + b+sqrt{a^2+b} = 31$. We can now solve for $b$ in terms of $a$.
$endgroup$
– jordan_glen
Jan 19 at 20:09




$begingroup$
The hypotenuse has length $sqrt{a^2+b^2}$, by the Pythagorean identity. So we have that $a + b+sqrt{a^2+b} = 31$. We can now solve for $b$ in terms of $a$.
$endgroup$
– jordan_glen
Jan 19 at 20:09










2 Answers
2






active

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Using the Pythagorean theorem, the hypotenuse, $$c,=sqrt{a^2+b^2}$$ $$a+b+c=p$$ Combining the two equations gives $$a+b+sqrt{a^2+b^2}=p$$ Subtracting by $a+b$ and squaring yields $$a^2+b^2=(p-a-b)^2=p^2+a^2+b^2-2ap-2bp+2ab$$ Subtracting by $a^2-b^2$ yields $$p^2-2ap-2bp+2ab=0$$ This can then be rearranged and factored as $$b(2a-2p)=2ap-p^2$$ Dividing by $2a-2p$ yields $$b = frac{2ap-p^2}{2a-2p}$$






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    0












    $begingroup$

    We have $$p=a+b+sqrt{a^2+b^2}$$ so $$p-sqrt{a^2+b^2}=a+b$$ after squaring we get
    $$p^2-2ab=2psqrt{a^2+b^2}$$ and now square again.
    And we get $$a=frac{1}{2}frac{p(2b-p)}{b-p}$$






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      2 Answers
      2






      active

      oldest

      votes








      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      1












      $begingroup$

      Using the Pythagorean theorem, the hypotenuse, $$c,=sqrt{a^2+b^2}$$ $$a+b+c=p$$ Combining the two equations gives $$a+b+sqrt{a^2+b^2}=p$$ Subtracting by $a+b$ and squaring yields $$a^2+b^2=(p-a-b)^2=p^2+a^2+b^2-2ap-2bp+2ab$$ Subtracting by $a^2-b^2$ yields $$p^2-2ap-2bp+2ab=0$$ This can then be rearranged and factored as $$b(2a-2p)=2ap-p^2$$ Dividing by $2a-2p$ yields $$b = frac{2ap-p^2}{2a-2p}$$






      share|cite|improve this answer









      $endgroup$


















        1












        $begingroup$

        Using the Pythagorean theorem, the hypotenuse, $$c,=sqrt{a^2+b^2}$$ $$a+b+c=p$$ Combining the two equations gives $$a+b+sqrt{a^2+b^2}=p$$ Subtracting by $a+b$ and squaring yields $$a^2+b^2=(p-a-b)^2=p^2+a^2+b^2-2ap-2bp+2ab$$ Subtracting by $a^2-b^2$ yields $$p^2-2ap-2bp+2ab=0$$ This can then be rearranged and factored as $$b(2a-2p)=2ap-p^2$$ Dividing by $2a-2p$ yields $$b = frac{2ap-p^2}{2a-2p}$$






        share|cite|improve this answer









        $endgroup$
















          1












          1








          1





          $begingroup$

          Using the Pythagorean theorem, the hypotenuse, $$c,=sqrt{a^2+b^2}$$ $$a+b+c=p$$ Combining the two equations gives $$a+b+sqrt{a^2+b^2}=p$$ Subtracting by $a+b$ and squaring yields $$a^2+b^2=(p-a-b)^2=p^2+a^2+b^2-2ap-2bp+2ab$$ Subtracting by $a^2-b^2$ yields $$p^2-2ap-2bp+2ab=0$$ This can then be rearranged and factored as $$b(2a-2p)=2ap-p^2$$ Dividing by $2a-2p$ yields $$b = frac{2ap-p^2}{2a-2p}$$






          share|cite|improve this answer









          $endgroup$



          Using the Pythagorean theorem, the hypotenuse, $$c,=sqrt{a^2+b^2}$$ $$a+b+c=p$$ Combining the two equations gives $$a+b+sqrt{a^2+b^2}=p$$ Subtracting by $a+b$ and squaring yields $$a^2+b^2=(p-a-b)^2=p^2+a^2+b^2-2ap-2bp+2ab$$ Subtracting by $a^2-b^2$ yields $$p^2-2ap-2bp+2ab=0$$ This can then be rearranged and factored as $$b(2a-2p)=2ap-p^2$$ Dividing by $2a-2p$ yields $$b = frac{2ap-p^2}{2a-2p}$$







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Jan 19 at 20:17









          LittleKnownMathematicianLittleKnownMathematician

          507




          507























              0












              $begingroup$

              We have $$p=a+b+sqrt{a^2+b^2}$$ so $$p-sqrt{a^2+b^2}=a+b$$ after squaring we get
              $$p^2-2ab=2psqrt{a^2+b^2}$$ and now square again.
              And we get $$a=frac{1}{2}frac{p(2b-p)}{b-p}$$






              share|cite|improve this answer









              $endgroup$


















                0












                $begingroup$

                We have $$p=a+b+sqrt{a^2+b^2}$$ so $$p-sqrt{a^2+b^2}=a+b$$ after squaring we get
                $$p^2-2ab=2psqrt{a^2+b^2}$$ and now square again.
                And we get $$a=frac{1}{2}frac{p(2b-p)}{b-p}$$






                share|cite|improve this answer









                $endgroup$
















                  0












                  0








                  0





                  $begingroup$

                  We have $$p=a+b+sqrt{a^2+b^2}$$ so $$p-sqrt{a^2+b^2}=a+b$$ after squaring we get
                  $$p^2-2ab=2psqrt{a^2+b^2}$$ and now square again.
                  And we get $$a=frac{1}{2}frac{p(2b-p)}{b-p}$$






                  share|cite|improve this answer









                  $endgroup$



                  We have $$p=a+b+sqrt{a^2+b^2}$$ so $$p-sqrt{a^2+b^2}=a+b$$ after squaring we get
                  $$p^2-2ab=2psqrt{a^2+b^2}$$ and now square again.
                  And we get $$a=frac{1}{2}frac{p(2b-p)}{b-p}$$







                  share|cite|improve this answer












                  share|cite|improve this answer



                  share|cite|improve this answer










                  answered Jan 19 at 20:13









                  Dr. Sonnhard GraubnerDr. Sonnhard Graubner

                  76.7k42866




                  76.7k42866















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