A circle has a radius of \blue{9}9start color #6495ed, 9, end color #6495ed. An arc in this circle has a central angle of 120^\circ120 ∘ 120, degrees. What is the length of the arc? Either enter an exact answer in terms of \piπpi or use 3.143.143, point, 14 for \piπpi and enter your answer as a decimal.