Answer:
2.28 cm
Step-by-step explanation:
Radius of the proton if v and B is perpendicular will be,

Now,
mass of proton,
.
Radius of the orbit,
.
Magnetic field,
.
Charge on the proton,
.
Now substitute all the variables in r.
.
.
Therefore the radius of the orbit of moving proton is 2.28 cm.