Здравейте, може ли помощ с тази задача

[Гост]

Благодаря предварително

[ammornil]

[tex]\triangle{ABC} \rightarrow \alpha+\beta+\gamma=180^{\circ} \Rightarrow \gamma=180^{\circ}-(\alpha+\beta)[/tex]

[tex]\cos{\gamma}=\cos{[180^{\circ}-(\alpha+\beta)]}=-\cos{(\alpha+\beta)}=-\left(-\frac{1}{3}\right)=\frac{1}{3}[/tex]

[tex]\sin{\gamma}=\sqrt{1-\cos^{2}{\gamma}}=\frac{2\sqrt{2}}{3}[/tex]

[tex]\frac{c}{\sin{\gamma}}=2\cdot R \Rightarrow[/tex] $$ R=\frac{c}{2\cdot \sin{\gamma}}=\frac{12}{2\cdot \frac{\normalsize{2\sqrt{2}}}{\normalsize{3}}}=\frac{9\sqrt{2}}{2}[cm] $$