Question

Un romb cu perimetrul de 20 cm si o diagonala egala cu 6 m are aria egala cu?

Answer 1

fie ABCD romb
P=AB+BC+CD+DA=20
AB=BC=CD=DA=5 cm
DB=6 cm diagonala DO=OB=3
in triunghiul AOD dreptunghic aplicam teorema PITAGORA AO^2=AD^2-OD^2
AO^2=25-9
AO^2=16
AO=4 cm
AC=8 cm diagonala AO=OC=4 CM
A=(diagonala1xdiagonala2):2=(DBXAC):2=(6X8):2=24 cm