A shaded portion of a circle is called a sector. Its area is a fraction of the area of the circle. To
find the area of a sector, first find the area of the circle. The formula for the area of a circle is
π × radius2. You must work backward from the circumference to find the radius. The circumference of a circle is 2π × radius. Therefore C = 8π, so 2πr = 8π, or r = 4. Area = πr2, or 16π.
Next, you know that the degrees in a circle total 360. The shaded portion has a 60-degree
angle, making it 1⁄6 (60⁄360) of the circle. Multiply the fraction by the area: 1⁄6 × 16π = 16⁄6π, or 8⁄3π,
which is less than 3π. Correct Answer: B.