Răspunsuri

2014-08-16T13:41:25+03:00
ABCD-trapez dreptunghic
mas<A=mas<D=90

fie [CN_|_ [AB]
[CN]-h

NB=AB-AN

AN=DC=6

NB=9-6
NB=3

ΔCNB, mas<N=90

CN²=BC²-NB²=5²-3²= 25-9=16   =>CN=6

A ABCD=(B+b)*h/2=  (6+9)*4/2= 15 *2 =30
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