Coordinate Geometry - Distance Formula












0












$begingroup$


If the points $A(4,3)$ and $B(x,5)$ are on the circle with center $O(2,3)$ find the value of $x$.



Since $AO=BO$
Using distance formula,
we get $x=2$



However my approach was why can't section formula be used where $(2,3)$ can be considered as the midpoint so that
$M = frac{x_1 + x_2}{2}$



I can't figure out the reason why this method doesn't work.
Any help will be appreciated.










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$endgroup$

















    0












    $begingroup$


    If the points $A(4,3)$ and $B(x,5)$ are on the circle with center $O(2,3)$ find the value of $x$.



    Since $AO=BO$
    Using distance formula,
    we get $x=2$



    However my approach was why can't section formula be used where $(2,3)$ can be considered as the midpoint so that
    $M = frac{x_1 + x_2}{2}$



    I can't figure out the reason why this method doesn't work.
    Any help will be appreciated.










    share|cite|improve this question











    $endgroup$















      0












      0








      0





      $begingroup$


      If the points $A(4,3)$ and $B(x,5)$ are on the circle with center $O(2,3)$ find the value of $x$.



      Since $AO=BO$
      Using distance formula,
      we get $x=2$



      However my approach was why can't section formula be used where $(2,3)$ can be considered as the midpoint so that
      $M = frac{x_1 + x_2}{2}$



      I can't figure out the reason why this method doesn't work.
      Any help will be appreciated.










      share|cite|improve this question











      $endgroup$




      If the points $A(4,3)$ and $B(x,5)$ are on the circle with center $O(2,3)$ find the value of $x$.



      Since $AO=BO$
      Using distance formula,
      we get $x=2$



      However my approach was why can't section formula be used where $(2,3)$ can be considered as the midpoint so that
      $M = frac{x_1 + x_2}{2}$



      I can't figure out the reason why this method doesn't work.
      Any help will be appreciated.







      geometry






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      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Dec 20 '18 at 12:16









      Matko

      864




      864










      asked Dec 20 '18 at 12:00









      Naimisha GirishNaimisha Girish

      14




      14






















          3 Answers
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          3












          $begingroup$

          That would require the line segment $AB$ to be the diameter for $M$ to be equal to $O$ which is not necessarily true.



          It is possible that $AB$ doesn't pass through $O$.






          share|cite|improve this answer









          $endgroup$





















            0












            $begingroup$

            You should sketch it on the cooredinate plane.



            $hspace{3cm}$![enter image description here



            If $A(4,3)$ lies on the circle with center $O(2,3)$, then $AO=2$ is the radius.



            The point $B(x,5)$ lies somewhere on the blue line $y=5$. In order for $B$ to lie on the circle too, it must be a common (touching or intersection) point of the circle and the blue line. And we see it is the touching point $B(2,5)$.



            When you consider $M(2,3)$ as the middle point of $AB$ and calculate $frac{x_1+x_2}{2}=frac{4+x}{2}=2 Rightarrow x=0$, you will find the point $C(0,3)$ which is on the circle, but it is not on the blue line. Also, $frac{y_1+y_2}{2}=frac{3+5}{2}=4ne 3$.






            share|cite|improve this answer









            $endgroup$





















              0












              $begingroup$

              Note : $AB$ is a chord.



              Midpoint: $M=(x/2+2,,4)$.



              1) Slope $AB$:



              $m_1:= dfrac{5-3}{x-4}=dfrac{2}{x-4}$.



              2) Slope $MO$:



              $m_2:= dfrac {4-3}{x/2+2 -2}=2/x.$



              $m_1$ is perpendicular to $m_2$ (why?):



              $m_1m_2=-1.$



              Hence $x/2-2=- x/2;$



              $x=2$






              share|cite|improve this answer











              $endgroup$













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                3 Answers
                3






                active

                oldest

                votes








                3 Answers
                3






                active

                oldest

                votes









                active

                oldest

                votes






                active

                oldest

                votes









                3












                $begingroup$

                That would require the line segment $AB$ to be the diameter for $M$ to be equal to $O$ which is not necessarily true.



                It is possible that $AB$ doesn't pass through $O$.






                share|cite|improve this answer









                $endgroup$


















                  3












                  $begingroup$

                  That would require the line segment $AB$ to be the diameter for $M$ to be equal to $O$ which is not necessarily true.



                  It is possible that $AB$ doesn't pass through $O$.






                  share|cite|improve this answer









                  $endgroup$
















                    3












                    3








                    3





                    $begingroup$

                    That would require the line segment $AB$ to be the diameter for $M$ to be equal to $O$ which is not necessarily true.



                    It is possible that $AB$ doesn't pass through $O$.






                    share|cite|improve this answer









                    $endgroup$



                    That would require the line segment $AB$ to be the diameter for $M$ to be equal to $O$ which is not necessarily true.



                    It is possible that $AB$ doesn't pass through $O$.







                    share|cite|improve this answer












                    share|cite|improve this answer



                    share|cite|improve this answer










                    answered Dec 20 '18 at 12:12









                    Siong Thye GohSiong Thye Goh

                    101k1466118




                    101k1466118























                        0












                        $begingroup$

                        You should sketch it on the cooredinate plane.



                        $hspace{3cm}$![enter image description here



                        If $A(4,3)$ lies on the circle with center $O(2,3)$, then $AO=2$ is the radius.



                        The point $B(x,5)$ lies somewhere on the blue line $y=5$. In order for $B$ to lie on the circle too, it must be a common (touching or intersection) point of the circle and the blue line. And we see it is the touching point $B(2,5)$.



                        When you consider $M(2,3)$ as the middle point of $AB$ and calculate $frac{x_1+x_2}{2}=frac{4+x}{2}=2 Rightarrow x=0$, you will find the point $C(0,3)$ which is on the circle, but it is not on the blue line. Also, $frac{y_1+y_2}{2}=frac{3+5}{2}=4ne 3$.






                        share|cite|improve this answer









                        $endgroup$


















                          0












                          $begingroup$

                          You should sketch it on the cooredinate plane.



                          $hspace{3cm}$![enter image description here



                          If $A(4,3)$ lies on the circle with center $O(2,3)$, then $AO=2$ is the radius.



                          The point $B(x,5)$ lies somewhere on the blue line $y=5$. In order for $B$ to lie on the circle too, it must be a common (touching or intersection) point of the circle and the blue line. And we see it is the touching point $B(2,5)$.



                          When you consider $M(2,3)$ as the middle point of $AB$ and calculate $frac{x_1+x_2}{2}=frac{4+x}{2}=2 Rightarrow x=0$, you will find the point $C(0,3)$ which is on the circle, but it is not on the blue line. Also, $frac{y_1+y_2}{2}=frac{3+5}{2}=4ne 3$.






                          share|cite|improve this answer









                          $endgroup$
















                            0












                            0








                            0





                            $begingroup$

                            You should sketch it on the cooredinate plane.



                            $hspace{3cm}$![enter image description here



                            If $A(4,3)$ lies on the circle with center $O(2,3)$, then $AO=2$ is the radius.



                            The point $B(x,5)$ lies somewhere on the blue line $y=5$. In order for $B$ to lie on the circle too, it must be a common (touching or intersection) point of the circle and the blue line. And we see it is the touching point $B(2,5)$.



                            When you consider $M(2,3)$ as the middle point of $AB$ and calculate $frac{x_1+x_2}{2}=frac{4+x}{2}=2 Rightarrow x=0$, you will find the point $C(0,3)$ which is on the circle, but it is not on the blue line. Also, $frac{y_1+y_2}{2}=frac{3+5}{2}=4ne 3$.






                            share|cite|improve this answer









                            $endgroup$



                            You should sketch it on the cooredinate plane.



                            $hspace{3cm}$![enter image description here



                            If $A(4,3)$ lies on the circle with center $O(2,3)$, then $AO=2$ is the radius.



                            The point $B(x,5)$ lies somewhere on the blue line $y=5$. In order for $B$ to lie on the circle too, it must be a common (touching or intersection) point of the circle and the blue line. And we see it is the touching point $B(2,5)$.



                            When you consider $M(2,3)$ as the middle point of $AB$ and calculate $frac{x_1+x_2}{2}=frac{4+x}{2}=2 Rightarrow x=0$, you will find the point $C(0,3)$ which is on the circle, but it is not on the blue line. Also, $frac{y_1+y_2}{2}=frac{3+5}{2}=4ne 3$.







                            share|cite|improve this answer












                            share|cite|improve this answer



                            share|cite|improve this answer










                            answered Dec 20 '18 at 13:31









                            farruhotafarruhota

                            20.3k2739




                            20.3k2739























                                0












                                $begingroup$

                                Note : $AB$ is a chord.



                                Midpoint: $M=(x/2+2,,4)$.



                                1) Slope $AB$:



                                $m_1:= dfrac{5-3}{x-4}=dfrac{2}{x-4}$.



                                2) Slope $MO$:



                                $m_2:= dfrac {4-3}{x/2+2 -2}=2/x.$



                                $m_1$ is perpendicular to $m_2$ (why?):



                                $m_1m_2=-1.$



                                Hence $x/2-2=- x/2;$



                                $x=2$






                                share|cite|improve this answer











                                $endgroup$


















                                  0












                                  $begingroup$

                                  Note : $AB$ is a chord.



                                  Midpoint: $M=(x/2+2,,4)$.



                                  1) Slope $AB$:



                                  $m_1:= dfrac{5-3}{x-4}=dfrac{2}{x-4}$.



                                  2) Slope $MO$:



                                  $m_2:= dfrac {4-3}{x/2+2 -2}=2/x.$



                                  $m_1$ is perpendicular to $m_2$ (why?):



                                  $m_1m_2=-1.$



                                  Hence $x/2-2=- x/2;$



                                  $x=2$






                                  share|cite|improve this answer











                                  $endgroup$
















                                    0












                                    0








                                    0





                                    $begingroup$

                                    Note : $AB$ is a chord.



                                    Midpoint: $M=(x/2+2,,4)$.



                                    1) Slope $AB$:



                                    $m_1:= dfrac{5-3}{x-4}=dfrac{2}{x-4}$.



                                    2) Slope $MO$:



                                    $m_2:= dfrac {4-3}{x/2+2 -2}=2/x.$



                                    $m_1$ is perpendicular to $m_2$ (why?):



                                    $m_1m_2=-1.$



                                    Hence $x/2-2=- x/2;$



                                    $x=2$






                                    share|cite|improve this answer











                                    $endgroup$



                                    Note : $AB$ is a chord.



                                    Midpoint: $M=(x/2+2,,4)$.



                                    1) Slope $AB$:



                                    $m_1:= dfrac{5-3}{x-4}=dfrac{2}{x-4}$.



                                    2) Slope $MO$:



                                    $m_2:= dfrac {4-3}{x/2+2 -2}=2/x.$



                                    $m_1$ is perpendicular to $m_2$ (why?):



                                    $m_1m_2=-1.$



                                    Hence $x/2-2=- x/2;$



                                    $x=2$







                                    share|cite|improve this answer














                                    share|cite|improve this answer



                                    share|cite|improve this answer








                                    edited Dec 20 '18 at 15:05

























                                    answered Dec 20 '18 at 13:00









                                    Peter SzilasPeter Szilas

                                    11.3k2822




                                    11.3k2822






























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