Объяснение:

[tex]1) \cos( \beta ) = \frac{bc}{ab} \\ \frac{2}{3} = \frac{2}{x } \\ x = 3 \: cm \\ ac = \sqrt{9 - 4} \\ ac = \sqrt{5} \: cm[/tex]

[tex]2) \sin( \beta ) = \frac{ac}{ab} \\ \frac{1}{4} = \frac{3}{x } \\ x = 12 \: cm \\ cb = \sqrt{144 - 9} \\ cb = 3 \sqrt{15} \: cm[/tex]