Find the radius r of the circle if the area of the sector is 16 with the degree inside the circle being 120 degrees.
Sector Area = (1/2)*radius^2 * (theta in rads)
Note : 120 degrees = (2/3)pi rads
So we have
16 = (1/2) r^2 * (2/3)pi
16 = (pi/3) r^2 multiply both sides by (3/pi)
16 (3/pi) = r^2
48/pi = r^2 take the suare root on both sides
r ≈ 3.91 units