1) We can find the length of the arc by setting the formula:
[tex]\begin{gathered} Arc\:length:\frac{45}{360}\times2\pi(10) \\ \\ \frac{20\pi }{8} \\ \\ \frac{5\pi}{2}\:inches\quad \end{gathered}[/tex]Note that the length of that arc is a portion of the whole circumference.