In the diagram, the circle has center O. The shaded sector AOB has sector angle 90^\circ, and AB has arc length 2\pi units. The area of sector AOB is
Answer Choices
A. 4\pi
B. 16\pi
C. 6\pi
D. 24\pi
E. 8\pi
In the diagram, the circle has center O. The shaded sector AOB has sector angle 90^\circ, and AB has arc length 2\pi units. The area of sector AOB is
Answer Choices
A. 4\pi
B. 16\pi
C. 6\pi
D. 24\pi
E. 8\pi