[tex]a = 6 \ cm\\b = 12 \ cm\\\gamma = 120^{o}\\P = ?\\\\sin\gamma = sin120^{o} = sin(180^{o}-60^{o}) = sin60^{o} = \frac{\sqrt{3}}{2}\\\\P = \frac{1}{2}absin\gamma\\\\P = \frac{1}{2}\cdot6 \ cm\cdot12 \ cm\cdot\frac{\sqrt{3}}{2}\\\\\boxed{P = 18\sqrt{3} \ cm^{2}}\\\\P\approx18\cdot1,73 \ cm^{2} \approx31,14 \ cm^{2}[/tex]
