Question

determine em grau a medida do angulo 2 pi /3

Answer 1

O pi no circulo trigonométrico vale 180°, então basta substituir:

$\theta = \frac{2 \pi}{3} \\\\ \theta = \frac{2 \cdot 180}{3} \\\\ \theta = \frac{360}{3} \\\\ \boxed{\boxed{\theta = 120\°}}$

Answer 2

Veja que π/3 corresponde a 180/3 = 60°
Logo 2 π/3 corresponde a 2 x 60° = 120°