Given that the arc length is 4.189 cm and the radius is 3 cm, the size of the arc will found as follows; C=theta/360 πd suppose: size of arc=theta=x d=3*2=6 cm hence; 4.189=x/360*π*6 4.189=0.0524x x=4.189/0.0524 x=80.004° The size of the arc length is 80.004°