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2014-07-31T15:32:18+03:00
ABCD-paralelogram
AC;BD-diag
AC=BD
AC intersectat BD={O}

AO=OC=AC/2=24/2=12
DO=OB=DB/2=24/2=12

ΔAOD, mas<AOD=60
AO=OD=12                    ⇒ΔAOD-echilateral

c)ΔAOB ≈ ΔAOD  <=> A ΔAOB= l²√3/4=  12²√3/4= 144√3/4= 36√3

b)A ΔBCD= 2*A ΔAOB= 2*36√3=72√3

a)A ABCD =4* A ΔAOB=4 *36√3= 144√3

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