Monday, January 23, 2012

Problem 720: Excenter, Intersecting Circles, Angle, Measurement

Geometry Problem
Level: Mathematics Education, High School, Honors Geometry, College.

Click the figure below to see the problem 720 details.

Online Geometry Problem 720: Excenter, Intersecting Circles, Angle, Measurement.
at

1 comment:

  1. PravinJanuary 23, 2012 at 6:38 PM

    Let CO'D cut the circle (O') at E.
    By the result of Problem 719,
    E is the incentre of ∆ABC
    Observing that ED is a diameter of circle (O'),
    it follows that AD ⊥ AE, implying that
    AD is the external bisector of ∠CAB.
    By symmetry,
    BD is the exteral bisector of ∠CBA.
    Hence D is an excentre of ∆ABC

    ReplyDelete

Share your solution or comment below! Your input is valuable and may be shared with the community.