Resposta:
[tex]\textsf{Leia abaixo}[/tex]
Explicação passo a passo:
[tex]\mathsf{a^2 = b^2 + c^2 - 2\:.\:b\:.\:c\:.\:cos\:\Theta}[/tex]
[tex]\mathsf{x^2 = 4^2 + (6\sqrt{3})^2 - 2\:.\:2\:.\:6\sqrt{3}\:.\:cos\:30^{\circ}}[/tex]
[tex]\mathsf{x^2 = 16 + 108 - \not2\:.\:2\:.\:6\sqrt{3}\:.\:\dfrac{\sqrt{3}}{\not2}}[/tex]
[tex]\mathsf{x^2 = 124 - 36}[/tex]
[tex]\mathsf{x^2 = 88}[/tex]
[tex]\mathsf{x = \sqrt{2^2.22}}[/tex]
[tex]\boxed{\boxed{\mathsf{x = 2\sqrt{22}}}}[/tex]
