Monday, June 18, 2012

Problem 767: Equilateral Triangle, Circle tangent to a side, Tangent line, Measurement, Secant

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

This entry contributed by Ajit Athle.
Click the figure below to see the problem 767 details.

Online Geometry Problem 767: Equilateral Triangle, Circle tangent to a side, Tangent line, Measurement, Secant.

3 comments:

  1. By theTangent Theorem:
    m^2 = (m+n-d)(m+n-e); n^2=(m+n-g)(m+n-f)
    By the Secant Theorem:
    de = fg or fg - de = 0
    Then
    m^2 - n^2 = (m+n)(f+g-d-e)
    (m+n)(m-n) = (m+n)(f+g-d-e)
    m-n = f+g-d-e
    So:
    m + d + e = f + g + n

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  2. http://www.mathematica.gr/forum/viewtopic.php?f=22&t=27794&p=135568

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  3. https://goo.gl/photos/FUFbuawj6LN7feiG6

    Let N and P are the projection of O over AB and AC
    Let M is the midpoint of AC
    Note that N and P are the midpoints of ED and FG
    Observe that MT= ½(m-n)
    BN=1/2(d+e)=BQ
    BP=1/2(f+g)
    PQ=BP-BQ= ½(f+g-d-e)
    Since ABC is equilateral so angle(AC, NO)=angle (AO,BC)= 30 degrees
    And MT=PQ => ½(m-n)= ½(f+g-d-e)
    So m+d+e=n+f+g

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