Acircle has a radius of length r. if you mark off an arc on the circle of length 3r. what is the measurment of of the angkebthat sub tends the arc? a.3 radians b. 3pir radians c. 3r radians d. 3pi radians

The appropriate choice is ...
  A. 3 radians


Arc length (s) is given in terms of radius (r) and central angle (θ) in radians by the formula
  s = rθ

When you substitute your given information, you have
  3r = rθ
Dividing by r gives
  θ = 3 . . . . . . . radians