7.1 Exercise 18

In central pivot irrigation, which creates the field shapes similar to the image at the beginning of Equations and Inequalities, a large irrigation pipe on wheels rotates around a center point. A farmer has a central pivot system with a radius of 400 meters. If water restrictions only allow her to water 150 thousand square meters a day, what angle should she set the system to cover? Write the answer in radian measure to two decimal places.