Arc length formula:
![\begin{gathered} \text{Arc length=}(x)/(360)\cdot C \\ \\ C=2\pi r \\ r=\text{radius} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/nwjb2khnnlz8vp8fg7mkeuieeerkizinno.png)
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10. r= 15cm
Angle CED is supplementary with angle BEC (add up to 180°)
![\begin{gathered} m\angle\text{CED}+m\angle\text{BEC}=180 \\ \\ m\angle CED=180-m\angle BEC \\ m\angle CED=180-68 \\ m\angle CED=112 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/ldfvhty51zjfq58sw4hf1h804nyde7eiub.png)
Then, arc CD is:
![\begin{gathered} CD=(112)/(360)\cdot2\pi(15\operatorname{cm}) \\ \\ CD\approx29.32\operatorname{cm} \end{gathered}]()
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11. r=8ft
The measure of central angle MRQ is equal to the measure of the given arc MQ (162°) and this angle and angle NRP are vertical angles (have the same measure) then, angle MRN and QRP (also vertical angles) need to add up 360° with the other angles, use it to find the measure of angle MRN:
![\begin{gathered} m\angle NRP+m\angle NRP+m\angle MRN+m\angle QRP=360 \\ \\ 2m\angle NRP+2m\angle MRN=360 \\ 2(162)+2m\angle MRN=360 \\ 324+2m\angle MRN=360 \\ 2m\angle MRN=360-324 \\ m\angle MRN=(36)/(2) \\ \\ m\angle MRN=18 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/8thpf1jqyxe146e2kq9tm2gqr0cai5zuj5.png)
The angle for arc NMP is equal to the sum of angle MRP (180°) and angle MRN (18°).
Then, the length of arc NMP is:
![\begin{gathered} \text{NMP}=(180+18)/(360)\cdot2\pi(8ft) \\ \\ \text{NMP}=27.65ft \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/n5bqw7npymupaxtkexqqade74snivuq4kh.png)
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