How do we solve for $x$ using law of sines?











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How do we solve for $x$ using the law of sines?




Here's my attempt:



$$angle BDC = 180- 30 - 12 = 138^circ$$



So we have that



$$dfrac{sin 30 }{|DC|} = dfrac{sin 12}{|DB|} = dfrac{sin 138}{|BC|} $$



For $triangle{ABD}$



$$dfrac{sin 18 }{|AD|} = dfrac{sin 24}{|DB|}$$



And what I need to evaluate is



$$dfrac{sin x }{|DC|} = ? $$



Can you help me take it from here?










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  • What else is valid for the triangle?
    – greedoid
    Nov 28 at 21:18










  • observe that $angle BDA =138^circ$
    – Vasya
    Nov 28 at 21:31










  • You can use Trigonometric form of Ceva's theorem to find $x$.
    – Muralidharan
    Nov 28 at 21:43










  • note that $180-24-18=138$, thus $angle ADB=138$. This gives $$angle ADC=84$$
    – clathratus
    Nov 28 at 21:50










  • I want to directly solve for $x$ using Sine law. Can anyone provide an answer if that's possible?
    – Hamilton
    Nov 29 at 13:25















up vote
2
down vote

favorite













enter image description here



How do we solve for $x$ using the law of sines?




Here's my attempt:



$$angle BDC = 180- 30 - 12 = 138^circ$$



So we have that



$$dfrac{sin 30 }{|DC|} = dfrac{sin 12}{|DB|} = dfrac{sin 138}{|BC|} $$



For $triangle{ABD}$



$$dfrac{sin 18 }{|AD|} = dfrac{sin 24}{|DB|}$$



And what I need to evaluate is



$$dfrac{sin x }{|DC|} = ? $$



Can you help me take it from here?










share|cite|improve this question
























  • What else is valid for the triangle?
    – greedoid
    Nov 28 at 21:18










  • observe that $angle BDA =138^circ$
    – Vasya
    Nov 28 at 21:31










  • You can use Trigonometric form of Ceva's theorem to find $x$.
    – Muralidharan
    Nov 28 at 21:43










  • note that $180-24-18=138$, thus $angle ADB=138$. This gives $$angle ADC=84$$
    – clathratus
    Nov 28 at 21:50










  • I want to directly solve for $x$ using Sine law. Can anyone provide an answer if that's possible?
    – Hamilton
    Nov 29 at 13:25













up vote
2
down vote

favorite









up vote
2
down vote

favorite












enter image description here



How do we solve for $x$ using the law of sines?




Here's my attempt:



$$angle BDC = 180- 30 - 12 = 138^circ$$



So we have that



$$dfrac{sin 30 }{|DC|} = dfrac{sin 12}{|DB|} = dfrac{sin 138}{|BC|} $$



For $triangle{ABD}$



$$dfrac{sin 18 }{|AD|} = dfrac{sin 24}{|DB|}$$



And what I need to evaluate is



$$dfrac{sin x }{|DC|} = ? $$



Can you help me take it from here?










share|cite|improve this question
















enter image description here



How do we solve for $x$ using the law of sines?




Here's my attempt:



$$angle BDC = 180- 30 - 12 = 138^circ$$



So we have that



$$dfrac{sin 30 }{|DC|} = dfrac{sin 12}{|DB|} = dfrac{sin 138}{|BC|} $$



For $triangle{ABD}$



$$dfrac{sin 18 }{|AD|} = dfrac{sin 24}{|DB|}$$



And what I need to evaluate is



$$dfrac{sin x }{|DC|} = ? $$



Can you help me take it from here?







trigonometry triangle






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Nov 28 at 22:58









clathratus

2,735326




2,735326










asked Nov 28 at 21:14









Hamilton

1838




1838












  • What else is valid for the triangle?
    – greedoid
    Nov 28 at 21:18










  • observe that $angle BDA =138^circ$
    – Vasya
    Nov 28 at 21:31










  • You can use Trigonometric form of Ceva's theorem to find $x$.
    – Muralidharan
    Nov 28 at 21:43










  • note that $180-24-18=138$, thus $angle ADB=138$. This gives $$angle ADC=84$$
    – clathratus
    Nov 28 at 21:50










  • I want to directly solve for $x$ using Sine law. Can anyone provide an answer if that's possible?
    – Hamilton
    Nov 29 at 13:25


















  • What else is valid for the triangle?
    – greedoid
    Nov 28 at 21:18










  • observe that $angle BDA =138^circ$
    – Vasya
    Nov 28 at 21:31










  • You can use Trigonometric form of Ceva's theorem to find $x$.
    – Muralidharan
    Nov 28 at 21:43










  • note that $180-24-18=138$, thus $angle ADB=138$. This gives $$angle ADC=84$$
    – clathratus
    Nov 28 at 21:50










  • I want to directly solve for $x$ using Sine law. Can anyone provide an answer if that's possible?
    – Hamilton
    Nov 29 at 13:25
















What else is valid for the triangle?
– greedoid
Nov 28 at 21:18




What else is valid for the triangle?
– greedoid
Nov 28 at 21:18












observe that $angle BDA =138^circ$
– Vasya
Nov 28 at 21:31




observe that $angle BDA =138^circ$
– Vasya
Nov 28 at 21:31












You can use Trigonometric form of Ceva's theorem to find $x$.
– Muralidharan
Nov 28 at 21:43




You can use Trigonometric form of Ceva's theorem to find $x$.
– Muralidharan
Nov 28 at 21:43












note that $180-24-18=138$, thus $angle ADB=138$. This gives $$angle ADC=84$$
– clathratus
Nov 28 at 21:50




note that $180-24-18=138$, thus $angle ADB=138$. This gives $$angle ADC=84$$
– clathratus
Nov 28 at 21:50












I want to directly solve for $x$ using Sine law. Can anyone provide an answer if that's possible?
– Hamilton
Nov 29 at 13:25




I want to directly solve for $x$ using Sine law. Can anyone provide an answer if that's possible?
– Hamilton
Nov 29 at 13:25










2 Answers
2






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1
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This works if you know what $|BC|$ and $|AC|$ are.



$$frac{sin(x+24)}{|BC|}=frac{sin48}{|AC|}$$
$$sin(x+24)=frac{|BC|sin48}{|AC|}$$
$$x+24=arcsinbigg(frac{|BC|sin48}{|AC|}bigg)$$
$$x=arcsinbigg(frac{|BC|sin48}{|AC|}bigg)-24$$






share|cite|improve this answer




























    up vote
    0
    down vote













    Recall that the angles of a triangle must add up to 180°. From this we can conclude that angle $CDB$ measures 138° and angle $BDA$ measures 138°. Therefore angle $ADC$ measures 84°. Now, if we let $y$ be the measure of angle $DCA$ (in degrees), we have the following system of equations.



    $$ begin{array}{rcr} x + y + 84 & = & 180 \ x + y + 84 & = & 180 end{array} $$



    So I want to say there will be infinitely many solutions... apparently there is some freedom in choosing the sides, as the other answer has hinted. But not 100% sure. Anyone else want to weigh in?






    share|cite|improve this answer





















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      2 Answers
      2






      active

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      2 Answers
      2






      active

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      active

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      up vote
      1
      down vote













      This works if you know what $|BC|$ and $|AC|$ are.



      $$frac{sin(x+24)}{|BC|}=frac{sin48}{|AC|}$$
      $$sin(x+24)=frac{|BC|sin48}{|AC|}$$
      $$x+24=arcsinbigg(frac{|BC|sin48}{|AC|}bigg)$$
      $$x=arcsinbigg(frac{|BC|sin48}{|AC|}bigg)-24$$






      share|cite|improve this answer

























        up vote
        1
        down vote













        This works if you know what $|BC|$ and $|AC|$ are.



        $$frac{sin(x+24)}{|BC|}=frac{sin48}{|AC|}$$
        $$sin(x+24)=frac{|BC|sin48}{|AC|}$$
        $$x+24=arcsinbigg(frac{|BC|sin48}{|AC|}bigg)$$
        $$x=arcsinbigg(frac{|BC|sin48}{|AC|}bigg)-24$$






        share|cite|improve this answer























          up vote
          1
          down vote










          up vote
          1
          down vote









          This works if you know what $|BC|$ and $|AC|$ are.



          $$frac{sin(x+24)}{|BC|}=frac{sin48}{|AC|}$$
          $$sin(x+24)=frac{|BC|sin48}{|AC|}$$
          $$x+24=arcsinbigg(frac{|BC|sin48}{|AC|}bigg)$$
          $$x=arcsinbigg(frac{|BC|sin48}{|AC|}bigg)-24$$






          share|cite|improve this answer












          This works if you know what $|BC|$ and $|AC|$ are.



          $$frac{sin(x+24)}{|BC|}=frac{sin48}{|AC|}$$
          $$sin(x+24)=frac{|BC|sin48}{|AC|}$$
          $$x+24=arcsinbigg(frac{|BC|sin48}{|AC|}bigg)$$
          $$x=arcsinbigg(frac{|BC|sin48}{|AC|}bigg)-24$$







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Nov 28 at 21:57









          clathratus

          2,735326




          2,735326






















              up vote
              0
              down vote













              Recall that the angles of a triangle must add up to 180°. From this we can conclude that angle $CDB$ measures 138° and angle $BDA$ measures 138°. Therefore angle $ADC$ measures 84°. Now, if we let $y$ be the measure of angle $DCA$ (in degrees), we have the following system of equations.



              $$ begin{array}{rcr} x + y + 84 & = & 180 \ x + y + 84 & = & 180 end{array} $$



              So I want to say there will be infinitely many solutions... apparently there is some freedom in choosing the sides, as the other answer has hinted. But not 100% sure. Anyone else want to weigh in?






              share|cite|improve this answer

























                up vote
                0
                down vote













                Recall that the angles of a triangle must add up to 180°. From this we can conclude that angle $CDB$ measures 138° and angle $BDA$ measures 138°. Therefore angle $ADC$ measures 84°. Now, if we let $y$ be the measure of angle $DCA$ (in degrees), we have the following system of equations.



                $$ begin{array}{rcr} x + y + 84 & = & 180 \ x + y + 84 & = & 180 end{array} $$



                So I want to say there will be infinitely many solutions... apparently there is some freedom in choosing the sides, as the other answer has hinted. But not 100% sure. Anyone else want to weigh in?






                share|cite|improve this answer























                  up vote
                  0
                  down vote










                  up vote
                  0
                  down vote









                  Recall that the angles of a triangle must add up to 180°. From this we can conclude that angle $CDB$ measures 138° and angle $BDA$ measures 138°. Therefore angle $ADC$ measures 84°. Now, if we let $y$ be the measure of angle $DCA$ (in degrees), we have the following system of equations.



                  $$ begin{array}{rcr} x + y + 84 & = & 180 \ x + y + 84 & = & 180 end{array} $$



                  So I want to say there will be infinitely many solutions... apparently there is some freedom in choosing the sides, as the other answer has hinted. But not 100% sure. Anyone else want to weigh in?






                  share|cite|improve this answer












                  Recall that the angles of a triangle must add up to 180°. From this we can conclude that angle $CDB$ measures 138° and angle $BDA$ measures 138°. Therefore angle $ADC$ measures 84°. Now, if we let $y$ be the measure of angle $DCA$ (in degrees), we have the following system of equations.



                  $$ begin{array}{rcr} x + y + 84 & = & 180 \ x + y + 84 & = & 180 end{array} $$



                  So I want to say there will be infinitely many solutions... apparently there is some freedom in choosing the sides, as the other answer has hinted. But not 100% sure. Anyone else want to weigh in?







                  share|cite|improve this answer












                  share|cite|improve this answer



                  share|cite|improve this answer










                  answered Nov 29 at 11:40









                  Nikifuj908

                  635




                  635






























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