Answer:
19.54 m
Step-by-step explanation:
[tex]l(\widehat {AB}) = \frac{ \theta}{360 \degree} \times 2 \pi r \\ \\l(\widehat {AB}) = \frac{140 \degree}{360 \degree} \times 2 \times 3.14 \times 8 \\ \\ l(\widehat {AB}) = \frac{7}{18} \times 2 \times 3.14 \times 8 \\ \\ l(\widehat {AB}) = \frac{351.68}{18} \\ \\ l(\widehat {AB}) = 19.5377778 \\ \\ l(\widehat {AB}) \approx 19.54 \: m[/tex]