Question

pararelogramul ABCD are BD _|_ AD unghiul A=60° si BC=9 cm perimetrul paralelogramului este egala cu:A. 42 cm B. 48 cm C. 54cm D. 56 cm​

Answer 1

$\it AD=BC=9\ cm\ (laturi\ opuse)\\ \\ \Delta ABD-\ dreptunghic,\ \widehat{BDA}=90^o,\ \widehat{DAB}=60^o,\ \Rightarrow \widehat{ABD}=30^o\\ \\ Th.\ \angle\ 30^o \Rightarrow AB=2\cdot AD=2\cdot9=18\ cm\\ \\ \mathcal{P}=2(AB+BC)=2((+!*)=2\cdot27=54\ cm$