question on plane geometry

• amaths

  22 May 09, 10:52

  Hello, would be grateful if anyone can provide the proofs to the below questions. Thanks.

  ===

  In the trapezium ABCD, AD is parallel to BC, BC = 3AD and the diagonals AC and BD meet at E. The line through A is drawn parallel to DB to meet the extended line of CB at F. Prove that

   

  (a) FB = AD

  (b) EC = 3AE

   

   

  

• eagle

  22 May 09, 11:04

  hi

  can upload the graphic to http://xs.to?

  My office blocks other pic-sharing sites...

• amaths

  22 May 09, 11:10

  Hi, eagle, please advise me how to upload the image. It is in jpg format. Thanks and cheers.

• syncopation_music

  22 May 09, 11:13

  Originally posted by amaths:

  Hi, eagle, please advise me how to upload the image. It is in jpg format. Thanks and cheers.

  register with photobucket

   

  then copy the url source to the clipboard

  then u paste it when u post on the forum ...

  u see the "tree " icon ?

  that is for u to post image

   

   

• eagle

  22 May 09, 11:22

  Originally posted by amaths:

  Hi, eagle, please advise me how to upload the image. It is in jpg format. Thanks and cheers.

  just upload

  there's a browse button on the website. No sign-ups or registrations needed

• amaths

  22 May 09, 11:24

  Hi, all, thanks.  Have managed to upload the diagram. Hope it is working. Cheers.

  

• amaths

  22 May 09, 11:34

  Hi, all, somehow, the picture does not appear to have been uploaded.

  Am posting the link below instead. Hope it works. Thanks and cheers.

  http://xs.to/xs.php?h=xs539&d=09214&f=plane_geometry-22may2009272.gif

  

   

• Forbiddensinner

  22 May 09, 12:03

  Originally posted by amaths:

  Hi, all, somehow, the picture does not appear to have been uploaded.

  Am posting the link below instead. Hope it works. Thanks and cheers.

  http://xs.to/xs.php?h=xs539&d=09214&f=plane_geometry-22may2009272.gif

  

   

  (a) Since AF is parallel to BD, and AD is parallel to BC ( while F is an extend of BC, hence making both FB and FC also parallel to AD ), ADBF must be a parallelogram, with FB = AD. ( Extra notes: The opposite sides of a parallelogram are always of equal lengths. )

   

  (b) Since BC = 3AD, and AD is parallel to BC, triangle AED and triangle BEC must be similar triangles. As triangle AED and triangle BEC are similar triangles, all sides of triangle BEC must be 3 times the similar sides of triangle AED, hence EC = 3AE.

• ??aaa??Wwqa

  19 Jul 09, 19:43

  [IMG]http://i628.photobucket.com/albums/uu10/finalpig/circle.jpg[/IMG]

• Forbiddensinner

  19 Jul 09, 19:55

  Originally posted by ??aaa??Wwqa:

  [IMG]http://i628.photobucket.com/albums/uu10/finalpig/circle.jpg[/IMG]

  Sgforums is different from other forums in the sense that putting [img] in front and [/img] behind of the image URL will not work.

  If you want to post up an image, here are the following steps which you must do :

  1) Right click the picture and press "Copy Image Location"

  2) Look at the toolbar above the space you are typing in. It includes Bold, Italic and Underline. All the way to the left, there is a tree-like icon. Press it.

  3) Paste what you have copied into "Image URL". You can use the rest of the settings to change the position and size of the picture.

  4) Press Insert to post up the image.

   

  On a side note, please create your own thread next time instead of hijacking that of someone else, especially if it is more than a month old.

• ??aaa??Wwqa

  19 Jul 09, 22:47

  ok