Question

Trigonometria, alguém pode ajudar?

Answer 1

$\displaystyle \underline{\text{Lei dos cossenos}}: \\\\ \text {x}^2=\text{AC}^2+\text{BC}^2-2.\text{AC.BC.cos}(70^\circ) \\\\ \text x^2=4^2+5^2-2.4.5.0,34 \\\\ \text x^2=16+25-13,6 \\\\ \text x^2=27,4 \\\\ \text{x}=\sqrt{27,4} \\\\\\ \huge\boxed{\ \text x \approx 5,23\ }\ \checkmark$