Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

What is the size of angle ABE?

  1. Sep 3, 2005 #1
    hi everyone, there si this problem that i can't figure out and i was looking for some help

    In a triangle ABC, angleBAC=35*, D is a point on AB such that AD=BC and angle ADC=110*. E is a point on AC such that BE=DC. What is the size of angle ABE????? :rofl:thx
  2. jcsd
  3. Sep 3, 2005 #2
    just draw and identify isosceles triangles.
    You will get 40 degrees
  4. Sep 7, 2005 #3
    i did what you said, but angle ABE was 70*
  5. Sep 7, 2005 #4
    ABE=40 degress.
    I think I have already posted it
  6. Sep 10, 2005 #5
    The solution:
    The symbol of degree is omitted.

    AD=BC (given)
    BE=DC (given)
    angleACD=180-angleBAC-angleADC (angle sum of triangle)
    Because angleACD=angleBAC
    Therefore DA=DC (sides opp. eq. angle)
    angleCDB=angleACD+angleCAD (ext. angle of triangle)
    angleCBD=angleCDB (base angles, isos. triangle)
    angleDCB=180-angleCBD-angleCDB (angle sum of triangle)
    angleCEB=angleECB (base angles, isos. triangle)
    angleABE+angleBAC=angleCEB (ext. angle of triangle)
    Last edited: Sep 10, 2005
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?