Kiselev's Geometry Problem 51












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I am going through Kiselev's Geometry, Book I.
I am having trouble with problem 51.
The problem states:




Give an example that disproves the proposition: "If the bisectors of two angles with a common vertex are perpendicular, then the angles are supplementary." Is the converse proposition true?




His definition of a supplementary angle goes as follows:




Two angles [...] are called supplementary if they have one common side, and their remaining two sides form continuations of each other. [...] the sum of two supplementary angles is 180°.




But I cannot see how to disprove that proposition using his definition. Is it something lost in translation or is it something that I am missing?










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    0












    $begingroup$


    I am going through Kiselev's Geometry, Book I.
    I am having trouble with problem 51.
    The problem states:




    Give an example that disproves the proposition: "If the bisectors of two angles with a common vertex are perpendicular, then the angles are supplementary." Is the converse proposition true?




    His definition of a supplementary angle goes as follows:




    Two angles [...] are called supplementary if they have one common side, and their remaining two sides form continuations of each other. [...] the sum of two supplementary angles is 180°.




    But I cannot see how to disprove that proposition using his definition. Is it something lost in translation or is it something that I am missing?










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      I am going through Kiselev's Geometry, Book I.
      I am having trouble with problem 51.
      The problem states:




      Give an example that disproves the proposition: "If the bisectors of two angles with a common vertex are perpendicular, then the angles are supplementary." Is the converse proposition true?




      His definition of a supplementary angle goes as follows:




      Two angles [...] are called supplementary if they have one common side, and their remaining two sides form continuations of each other. [...] the sum of two supplementary angles is 180°.




      But I cannot see how to disprove that proposition using his definition. Is it something lost in translation or is it something that I am missing?










      share|cite|improve this question









      $endgroup$




      I am going through Kiselev's Geometry, Book I.
      I am having trouble with problem 51.
      The problem states:




      Give an example that disproves the proposition: "If the bisectors of two angles with a common vertex are perpendicular, then the angles are supplementary." Is the converse proposition true?




      His definition of a supplementary angle goes as follows:




      Two angles [...] are called supplementary if they have one common side, and their remaining two sides form continuations of each other. [...] the sum of two supplementary angles is 180°.




      But I cannot see how to disprove that proposition using his definition. Is it something lost in translation or is it something that I am missing?







      geometry euclidean-geometry






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      asked Nov 28 '18 at 18:58









      Júlio CezarJúlio Cezar

      102




      102






















          2 Answers
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          Does this picture provide some help?
          enter image description here






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          • $begingroup$
            Yes, a lot, actually. I take that the converse proposition would then be "If two angles with a common vertex are supplementary, then the bisectors are perpendicular." and would be true?
            $endgroup$
            – Júlio Cezar
            Nov 28 '18 at 19:19



















          0












          $begingroup$

          Hint: Angles can share a vertex without sharing a side.






          share|cite|improve this answer









          $endgroup$













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            2 Answers
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            2 Answers
            2






            active

            oldest

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            active

            oldest

            votes






            active

            oldest

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            1












            $begingroup$

            Does this picture provide some help?
            enter image description here






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            • $begingroup$
              Yes, a lot, actually. I take that the converse proposition would then be "If two angles with a common vertex are supplementary, then the bisectors are perpendicular." and would be true?
              $endgroup$
              – Júlio Cezar
              Nov 28 '18 at 19:19
















            1












            $begingroup$

            Does this picture provide some help?
            enter image description here






            share|cite|improve this answer









            $endgroup$













            • $begingroup$
              Yes, a lot, actually. I take that the converse proposition would then be "If two angles with a common vertex are supplementary, then the bisectors are perpendicular." and would be true?
              $endgroup$
              – Júlio Cezar
              Nov 28 '18 at 19:19














            1












            1








            1





            $begingroup$

            Does this picture provide some help?
            enter image description here






            share|cite|improve this answer









            $endgroup$



            Does this picture provide some help?
            enter image description here







            share|cite|improve this answer












            share|cite|improve this answer



            share|cite|improve this answer










            answered Nov 28 '18 at 19:06









            Vasily MitchVasily Mitch

            1,35837




            1,35837












            • $begingroup$
              Yes, a lot, actually. I take that the converse proposition would then be "If two angles with a common vertex are supplementary, then the bisectors are perpendicular." and would be true?
              $endgroup$
              – Júlio Cezar
              Nov 28 '18 at 19:19


















            • $begingroup$
              Yes, a lot, actually. I take that the converse proposition would then be "If two angles with a common vertex are supplementary, then the bisectors are perpendicular." and would be true?
              $endgroup$
              – Júlio Cezar
              Nov 28 '18 at 19:19
















            $begingroup$
            Yes, a lot, actually. I take that the converse proposition would then be "If two angles with a common vertex are supplementary, then the bisectors are perpendicular." and would be true?
            $endgroup$
            – Júlio Cezar
            Nov 28 '18 at 19:19




            $begingroup$
            Yes, a lot, actually. I take that the converse proposition would then be "If two angles with a common vertex are supplementary, then the bisectors are perpendicular." and would be true?
            $endgroup$
            – Júlio Cezar
            Nov 28 '18 at 19:19











            0












            $begingroup$

            Hint: Angles can share a vertex without sharing a side.






            share|cite|improve this answer









            $endgroup$


















              0












              $begingroup$

              Hint: Angles can share a vertex without sharing a side.






              share|cite|improve this answer









              $endgroup$
















                0












                0








                0





                $begingroup$

                Hint: Angles can share a vertex without sharing a side.






                share|cite|improve this answer









                $endgroup$



                Hint: Angles can share a vertex without sharing a side.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Nov 28 '18 at 19:05









                ArthurArthur

                112k7107191




                112k7107191






























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