Gogeometry Problem 238

 dans Euclide Geometry Problem par Harvey Littleman

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From Gogeometry :

Using :

• Congruent triangles

• ΔABE is congruent to ΔBCF by rotation of pi/2 => <AGF=90°
• Define H as the middle of AB and K as the middle of AG
• By construction HD//BF
• AH=HB=>AK=KG
• <AGF=90° => <AKD=90°
• ΔDKG is congruent to ΔDKA (SAS)
• =>DG=DA
• Therefore a=b

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