Central angle of 135 degrees = 135 (Pi/180) = (3/4)Pi = 2.356 radians
First answer:
Central angle = 2.356 radians
Arc lenght = 2 Pi r (angle/360), in this case:
82 = 2 Pi r (135/360) = 2 Pi r (3/8) = (3/4) Pi r
82 = (3/4) Pi r
r = 82/(3/4)Pi = 82/2.35619449
r = 34.80188089
Second answer:
Radius = 34.8 miles