A sector of a circle is the region bounded by radii OA and OB and the intercepted arc $A B$. See the following figure. The area of the sector is given by
$$A=\frac{1}{2} r^{2} \theta$$
(GRAPH CAN'T COPY).
where $r$ is the radius of the circle and $\theta$ is the measure of the central angle in radians.
In Exercises 87 to $90,$ find the area, to the nearest square unit, of the sector of a circle with the given radius and central angle.
$$r=2.8 \text { feet, } \theta=\frac{5 \pi}{2} \text { radians }$$