Monday, May 19, 2008

Elearn Geometry Problem 62



See complete Problem 62
Square diagonal and Inscribed Circle. Level: High School, SAT Prep, College geometry

Post your solutions or ideas in the comments.

4 comments:

  1. Let A:(0,0),B:(0,s),C;(s,s) and D:(s,0) with s =side of square. Therefore,O:(s/2,s/2) & Arc BD: x^2+y^2=s^2 and the circle:(x-s/2)^2 + (y-s/2)^2 =s^2/4. E is:[(s(5 -V7)/8,s(V7+5)/8].
    Now,CE^2=[(s-(s(5-V7)/8)]^2+[s-s(V7+5)/8)]^2
    = s^2/2 or CE =s/V2
    But BD^2 = 2s^2 or BD = V2s which gives the desired result viz. CE = BD/2
    Ajit: ajitathle@gmail.com

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  2. http://henrik-geometry.webs.com/62.htm

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  3. Let AB = a so that OE = a/2 & OC = a/sqrt2

    Apply Apollonius to Tr. AEC

    a^2 + CE^2 = 2 (a^2/2 + a^2/4) from which
    CE = a/sqrt2 = OC

    Sumith Peiris
    Moratuwa
    Sri Lanka

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  4. AE^2=AO.AC, Hence triangle ACE is similar to triangle AEO. We have CE/AC=OE/AE,Since OE/AE=1/2, We get CE=AC/2.

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