Answer:
the radius of the circular target in the center is 2.12 feet
Step-by-step explanation:
the total area of the dartboard is
π x r² = π x 3² = 9π  (28.27 ft²)
The area of the actual target in the center needs to be half of the dartboard (4.5 π)  (14.14 ft²)
(Small area :  4.5π =  π x r²
           Divide both sides by  π
    4.5 = r²
    √4.5 = r
   r= 2.12132034.......  (2.12 feet)