Monday, January 23, 2012

Problem 719: Incenter, Intersecting Circles, Angle, Measurement

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

Click the figure below to see the problem 719 details.

Online Geometry Problem 719: Incenter, Intersecting Circles, Angle, Measurement.

1 comment:

  1. Equal arcs AO’, BO’ of circle (O) subtend equal angles at the circumference.
    So ∠ACO’ = ∠BCO’ and so
    CD bisects ∠ACB …… (i)
    Next ∠DAB =(1/2)∠DO’B referred to circle(O’)
    =(1/2)∠CO’B =(1/2)∠CAB referred to circle(O) and so
    AD bisects ∠CAB …… (ii)
    From (i) and (ii), it follows that
    D is the incentre of ∆ABC.

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