Question

задача на фото 10-11 клас ​

Answer 1

$\cos(150) = \cos(180 - 30) = - \cos(30) = - \frac{ \sqrt{3} }{2} \\ \cos(q) = \frac{a \times b}{ |a| \times |b| } \\ a \times b = |a| \times |b| \times \cos(q) = 2 \sqrt{3} \times \sqrt{3} \times ( - \frac{ \sqrt{3} }{2} ) = - 3 \sqrt{3}$