Find the degree measure of an arc of a circle












0












$begingroup$


Can anyone help me with this problem? I think I probably miss some theorems.



In teh figure angle AED = 30, and the minor arc AB, BC, and CD are all equal. The degree measure of the minor arc AD is



a) not enought information, b) 30, c) 105, d) 45, e) none of these.



enter image description here










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$endgroup$








  • 2




    $begingroup$
    You need to know the theorem that $[m(BC)-m(AD)]/2=30^circ$. I think that with that, you can answer the question.
    $endgroup$
    – Lubin
    Apr 16 '16 at 17:40












  • $begingroup$
    @Lubin Instead of remembering the theorem, I tried to prove it, but failed. Can you give me a hint on or show me how to prove the theorem? Thank you again.
    $endgroup$
    – user321645
    Apr 16 '16 at 18:01










  • $begingroup$
    Do you know the theorem that the if $A$, $B$, and $C$ are three points on the circumference of a circle, then the measure of angle $ACB$ is half the measure of the arc $AB$?
    $endgroup$
    – Lubin
    Apr 16 '16 at 18:04
















0












$begingroup$


Can anyone help me with this problem? I think I probably miss some theorems.



In teh figure angle AED = 30, and the minor arc AB, BC, and CD are all equal. The degree measure of the minor arc AD is



a) not enought information, b) 30, c) 105, d) 45, e) none of these.



enter image description here










share|cite|improve this question









$endgroup$








  • 2




    $begingroup$
    You need to know the theorem that $[m(BC)-m(AD)]/2=30^circ$. I think that with that, you can answer the question.
    $endgroup$
    – Lubin
    Apr 16 '16 at 17:40












  • $begingroup$
    @Lubin Instead of remembering the theorem, I tried to prove it, but failed. Can you give me a hint on or show me how to prove the theorem? Thank you again.
    $endgroup$
    – user321645
    Apr 16 '16 at 18:01










  • $begingroup$
    Do you know the theorem that the if $A$, $B$, and $C$ are three points on the circumference of a circle, then the measure of angle $ACB$ is half the measure of the arc $AB$?
    $endgroup$
    – Lubin
    Apr 16 '16 at 18:04














0












0








0


0



$begingroup$


Can anyone help me with this problem? I think I probably miss some theorems.



In teh figure angle AED = 30, and the minor arc AB, BC, and CD are all equal. The degree measure of the minor arc AD is



a) not enought information, b) 30, c) 105, d) 45, e) none of these.



enter image description here










share|cite|improve this question









$endgroup$




Can anyone help me with this problem? I think I probably miss some theorems.



In teh figure angle AED = 30, and the minor arc AB, BC, and CD are all equal. The degree measure of the minor arc AD is



a) not enought information, b) 30, c) 105, d) 45, e) none of these.



enter image description here







geometry






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share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Apr 16 '16 at 17:26







user321645















  • 2




    $begingroup$
    You need to know the theorem that $[m(BC)-m(AD)]/2=30^circ$. I think that with that, you can answer the question.
    $endgroup$
    – Lubin
    Apr 16 '16 at 17:40












  • $begingroup$
    @Lubin Instead of remembering the theorem, I tried to prove it, but failed. Can you give me a hint on or show me how to prove the theorem? Thank you again.
    $endgroup$
    – user321645
    Apr 16 '16 at 18:01










  • $begingroup$
    Do you know the theorem that the if $A$, $B$, and $C$ are three points on the circumference of a circle, then the measure of angle $ACB$ is half the measure of the arc $AB$?
    $endgroup$
    – Lubin
    Apr 16 '16 at 18:04














  • 2




    $begingroup$
    You need to know the theorem that $[m(BC)-m(AD)]/2=30^circ$. I think that with that, you can answer the question.
    $endgroup$
    – Lubin
    Apr 16 '16 at 17:40












  • $begingroup$
    @Lubin Instead of remembering the theorem, I tried to prove it, but failed. Can you give me a hint on or show me how to prove the theorem? Thank you again.
    $endgroup$
    – user321645
    Apr 16 '16 at 18:01










  • $begingroup$
    Do you know the theorem that the if $A$, $B$, and $C$ are three points on the circumference of a circle, then the measure of angle $ACB$ is half the measure of the arc $AB$?
    $endgroup$
    – Lubin
    Apr 16 '16 at 18:04








2




2




$begingroup$
You need to know the theorem that $[m(BC)-m(AD)]/2=30^circ$. I think that with that, you can answer the question.
$endgroup$
– Lubin
Apr 16 '16 at 17:40






$begingroup$
You need to know the theorem that $[m(BC)-m(AD)]/2=30^circ$. I think that with that, you can answer the question.
$endgroup$
– Lubin
Apr 16 '16 at 17:40














$begingroup$
@Lubin Instead of remembering the theorem, I tried to prove it, but failed. Can you give me a hint on or show me how to prove the theorem? Thank you again.
$endgroup$
– user321645
Apr 16 '16 at 18:01




$begingroup$
@Lubin Instead of remembering the theorem, I tried to prove it, but failed. Can you give me a hint on or show me how to prove the theorem? Thank you again.
$endgroup$
– user321645
Apr 16 '16 at 18:01












$begingroup$
Do you know the theorem that the if $A$, $B$, and $C$ are three points on the circumference of a circle, then the measure of angle $ACB$ is half the measure of the arc $AB$?
$endgroup$
– Lubin
Apr 16 '16 at 18:04




$begingroup$
Do you know the theorem that the if $A$, $B$, and $C$ are three points on the circumference of a circle, then the measure of angle $ACB$ is half the measure of the arc $AB$?
$endgroup$
– Lubin
Apr 16 '16 at 18:04










2 Answers
2






active

oldest

votes


















0












$begingroup$

A little bit more on how to prove this is as follows.



An inscribed angle is an angle whose vertex is on the circle and whose sides contain chords of the circle.



In the question angles BAC and ACD are inscribed angles.



If an angle is inscribe in a circle, then its measure is half the measure of its intercepted arc.



From this we conclude that angle BAC = (BC)/2 and angle ACD = (AD)/2.



Now from the exterior angle theorem we have.



Angle AED = abs[ angle BAC - angle ACD ]



Now if we substitute our previous equations into this exterior angle theorem we get.



Angle AED = abs [ (BC)/2 - (AD)/2]



The absolute value is there to make sure the angle is positive.



My final result is





which means that it depends on the radius r of the circle. So I don't think there is enough information to solve.






share|cite|improve this answer











$endgroup$





















    0












    $begingroup$

    From the symmetry that $AB=CD$, we know that $Delta BCE$ is isosceles and that lines $AD$ and $BC$ are parallel. We can add some angles to the original diagram:



    enter image description here



    The major arc $BD = 2cdot105^circ$, hence $AB=BC=CD=105^circ$ and minor arc $AD=45^circ$.






    share|cite|improve this answer









    $endgroup$













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      2 Answers
      2






      active

      oldest

      votes








      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      0












      $begingroup$

      A little bit more on how to prove this is as follows.



      An inscribed angle is an angle whose vertex is on the circle and whose sides contain chords of the circle.



      In the question angles BAC and ACD are inscribed angles.



      If an angle is inscribe in a circle, then its measure is half the measure of its intercepted arc.



      From this we conclude that angle BAC = (BC)/2 and angle ACD = (AD)/2.



      Now from the exterior angle theorem we have.



      Angle AED = abs[ angle BAC - angle ACD ]



      Now if we substitute our previous equations into this exterior angle theorem we get.



      Angle AED = abs [ (BC)/2 - (AD)/2]



      The absolute value is there to make sure the angle is positive.



      My final result is





      which means that it depends on the radius r of the circle. So I don't think there is enough information to solve.






      share|cite|improve this answer











      $endgroup$


















        0












        $begingroup$

        A little bit more on how to prove this is as follows.



        An inscribed angle is an angle whose vertex is on the circle and whose sides contain chords of the circle.



        In the question angles BAC and ACD are inscribed angles.



        If an angle is inscribe in a circle, then its measure is half the measure of its intercepted arc.



        From this we conclude that angle BAC = (BC)/2 and angle ACD = (AD)/2.



        Now from the exterior angle theorem we have.



        Angle AED = abs[ angle BAC - angle ACD ]



        Now if we substitute our previous equations into this exterior angle theorem we get.



        Angle AED = abs [ (BC)/2 - (AD)/2]



        The absolute value is there to make sure the angle is positive.



        My final result is





        which means that it depends on the radius r of the circle. So I don't think there is enough information to solve.






        share|cite|improve this answer











        $endgroup$
















          0












          0








          0





          $begingroup$

          A little bit more on how to prove this is as follows.



          An inscribed angle is an angle whose vertex is on the circle and whose sides contain chords of the circle.



          In the question angles BAC and ACD are inscribed angles.



          If an angle is inscribe in a circle, then its measure is half the measure of its intercepted arc.



          From this we conclude that angle BAC = (BC)/2 and angle ACD = (AD)/2.



          Now from the exterior angle theorem we have.



          Angle AED = abs[ angle BAC - angle ACD ]



          Now if we substitute our previous equations into this exterior angle theorem we get.



          Angle AED = abs [ (BC)/2 - (AD)/2]



          The absolute value is there to make sure the angle is positive.



          My final result is





          which means that it depends on the radius r of the circle. So I don't think there is enough information to solve.






          share|cite|improve this answer











          $endgroup$



          A little bit more on how to prove this is as follows.



          An inscribed angle is an angle whose vertex is on the circle and whose sides contain chords of the circle.



          In the question angles BAC and ACD are inscribed angles.



          If an angle is inscribe in a circle, then its measure is half the measure of its intercepted arc.



          From this we conclude that angle BAC = (BC)/2 and angle ACD = (AD)/2.



          Now from the exterior angle theorem we have.



          Angle AED = abs[ angle BAC - angle ACD ]



          Now if we substitute our previous equations into this exterior angle theorem we get.



          Angle AED = abs [ (BC)/2 - (AD)/2]



          The absolute value is there to make sure the angle is positive.



          My final result is





          which means that it depends on the radius r of the circle. So I don't think there is enough information to solve.







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited Mar 9 '17 at 17:33









          Community

          1




          1










          answered Apr 16 '16 at 20:12









          Erock BroxErock Brox

          23828




          23828























              0












              $begingroup$

              From the symmetry that $AB=CD$, we know that $Delta BCE$ is isosceles and that lines $AD$ and $BC$ are parallel. We can add some angles to the original diagram:



              enter image description here



              The major arc $BD = 2cdot105^circ$, hence $AB=BC=CD=105^circ$ and minor arc $AD=45^circ$.






              share|cite|improve this answer









              $endgroup$


















                0












                $begingroup$

                From the symmetry that $AB=CD$, we know that $Delta BCE$ is isosceles and that lines $AD$ and $BC$ are parallel. We can add some angles to the original diagram:



                enter image description here



                The major arc $BD = 2cdot105^circ$, hence $AB=BC=CD=105^circ$ and minor arc $AD=45^circ$.






                share|cite|improve this answer









                $endgroup$
















                  0












                  0








                  0





                  $begingroup$

                  From the symmetry that $AB=CD$, we know that $Delta BCE$ is isosceles and that lines $AD$ and $BC$ are parallel. We can add some angles to the original diagram:



                  enter image description here



                  The major arc $BD = 2cdot105^circ$, hence $AB=BC=CD=105^circ$ and minor arc $AD=45^circ$.






                  share|cite|improve this answer









                  $endgroup$



                  From the symmetry that $AB=CD$, we know that $Delta BCE$ is isosceles and that lines $AD$ and $BC$ are parallel. We can add some angles to the original diagram:



                  enter image description here



                  The major arc $BD = 2cdot105^circ$, hence $AB=BC=CD=105^circ$ and minor arc $AD=45^circ$.







                  share|cite|improve this answer












                  share|cite|improve this answer



                  share|cite|improve this answer










                  answered Nov 12 '17 at 10:38









                  nickgardnickgard

                  1,9301414




                  1,9301414






























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