Answer:
[tex] \frac{20}{3}\pi [/tex]
Step-by-step explanation:
[tex]l \widehat{(QR)} = \frac{ \theta}{360 \degree} \times 2\pi \: r \\ \\ = \frac{ 120 \degree}{360 \degree} \times 2\pi \times 10 \\ \\ = \frac{ 1}{3} \times 20\pi \\ \\ \huge \red{ \boxed{ l \widehat{(QR)} = \frac{20}{3}\pi }}[/tex]
