Find the length of red arc AB

The pro-football team had just finished its daily practice when a large turkey strutted onto the field. While the players gazed in amazement, the turkey walked up to the head coach and requested a tryout. Everyone stared in silence as the turkey caught pass after pass and ran through the defensive line. When the turkey returned to the sidelines, the coach shouted, “Your are terrific! Sign up for the season, and I’ll see to it that you get a huge signing bonus.” “Forget the bonus,” the turkey said. “All I want to know is, does the season go past Thanksgiving Day?”