Help with O level A Maths Geometric Proofs

• HomeWorkxD

  19 Nov 12, 10:40

  

  

  Need help with question 19c), 19d and 22b :(

• syncopation_music

  20 Nov 12, 03:33

  sound difficult , i let others answer you better :)

• Lee012lee

  25 Nov 12, 05:27

  Originally posted by HomeWorkxD:

  

  

  Need help with question 19c), 19d and 22b :(

  Dear TS,

  May I know where do the questions come from ie from your maths teacher, a book

  etc ?

  Thank you for your kind attention.

  Regards

  Lee012Lee

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  Question 19 

  (a)    Make use of the angle in a semi circle ie the midpoint of BP will be the

          centre

  (b)    It is to be noted that t = s and make use of angles in the same segment.

  (c)    At N, draw a line that is parallel to MP to meet the line AP at C

          ie NC will be s.

          At A, draw a perpendicular line to the parallel line to meet at D.

          Using similar triangles,

          TM/TB = ND/NA

          Since NC  <  ND  <  NA,

          r/p > s/u

  (d)   Since NC  <  ND  <  NA,

          s < u (shown)

  Note : The questions should have asked to show that s < u first before it asks to

             show s/u < r/p

   

• Lee012lee

  25 Nov 12, 05:32

  Question 22

  (a)      Use the AAA Rule to prove the similar triangles

  (b)      Use the ASA rule to prove that triangle PTS is congruent to RTS.

             Since the two triangles are congruent, SP = SR

  (c)       Use vectors and ratio theorem to show that RO=0.5(BS+QP)

             An easier method is to extend the line SP and BQ to meet at D to form

             triangles and use the ratio theorem to show that RO=0.5(BS+QP)