the arc is like the circumference, but only a fraction of it (like the crust of a pizza slice)
ok so find what fraction of the circumference that arc is
C=2pir
r=5
c=2pi5
c=10pi
2 out of 10pi=2/10pi=1/5pi
whole circle=360
1/5pi of 360=360/5pi=72/pi=72/3.14=22.9299
round
22.93 degrees