Friday, January 2, 2009

Elearn Geometry Problem 214: Quadrilateral, Angle Bisectors

 Geometry Problem 214: Quadrilateral, Angle Bisectors.

See complete Problem 214 at:
gogeometry.com/problem/p214_quadrilateral_angle_bisector.htm

Level: High School, SAT Prep, College geometry

2 comments:

  1. BAC + CDA + ABC + DCB = 360 (1)
    B/2 + C/2 + x = 180 (2)

    B + C = 360 - 2x
    B + C = 360 - A - D

    then 360 - 2x = 360 - A - D
    -2x = -A -D
    x = (A-D)/2

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  2. 1st mistake to the anonunous solution :
    In the 1st equation "BAC" should be replaced with BAD.
    2nd mistake : if -2X=-A-D then 2X=A+D, so X=(A+D)/2 and not X=(A-D)/2.
    Hoever his solution (with the above corrections) is right and elegant.
    G. Platis

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