Determining Radian Measure 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.