Circle O is shown. T O, Q O, P O, K O, and J O are radii. The measure of arc Q T is 0.14 r, the measure of arcs Q P, P K, and K J are r. The length of O J is 4. There are exactly π radians in a semicircle. There are exactly π radians in a full circle. There are approximately radians in a full circle. 2π radians is equivalent to degrees.