Sector area can be found with the formula [tex]A = \frac{\theta}{360} \pi r ^2[/tex] where [tex]\theta[/tex] is the central angle.
r = 8m , [tex]\theta[/tex] = 135º
[tex]A = \frac{135}{360} \pi (8)[/tex] m^2
Arc length formula is [tex]s = 2\pi r (\frac{\theta}{360} )\\[/tex]
[tex]s = 2\pi (8)(\frac{135}{360} )\\[/tex] m