[tex]Zadanie\\\\\frac{2}{l}=sin\ 30^o\\\\\frac{2}{l}=\frac{1}{2}\ \ \ \mid\cdot l\\\\2=\frac{1}{2}\cdot l\ \ \ \mid\cdot2\\\\l=4\\\\2^{2}+k^{2}=l^{2}\\\\4+k^{2}=4^{2}\ \ \ \mid-4\\\\ k^{2} =16-4\\\\k^{2} =12\\\\k=\sqrt{12} =\sqrt{4\cdot3}\\\\k=2\sqrt{3}\\\\Odp.\ B[/tex]
