It is required to find the area of the sector AOB in terms of π.
Notice that the central angle is 120º.
Recall that the Area of a sector is given as:
Where θ is the central angle and r is the radius.
Substitute θ=120º and r=9 into the formula:
Evaluate the expression on the right:
Hence, the required area of the sector in terms of π is 27π.