ASriia paralelogram=BC*CD*sin∡(BCD) cum sin120° nu stim in clasa 7-8 ,avem 2 varianate
varianta 1
Aria=AB *BC*sin∡(ABC)
AB=CD=12
BC=8
m∡(ABC)=180°-120°=60° (intr-un paralelogram unghiurile alaturate sunt suplementare)
Deci Aria =8*12*√3/2=48√3 cm²
varianta 2
Aria =BC*d(BC, AD)=8*sin 60°
Aria=12*8*sin 60°=48√3
d((BC, AD)=CD *sin∡(ADC)
