The question is incomplete. Doing some researh I found the complete question:
"A
circle has a central angle measuring (7pi/10) radians that intersects
an arc of length 33 cm. What is the length of the radius of the circle?
Round your answer to the nearest whole cm. Use 3.14 for pi"
With that the answer is: 15 cm.
This is how you do it, so you can work yourself this kind of problems.
1) Central angle of a whole circle is 2Ï€
2) The circumference (perimeter of the circle) is 2Ï€ * radius
3) The arc length and the central angles are proportional, meaning that:
 arc length          circumference
------------------ = -----------------------
central angle            2π
 arc length       2π*radius
----------------- = ---------------
central angle        2π
So, you can solve for the radius, simplifying the right side fraction by 2Ï€:
=> radius = arc length / central angle.
Now replace arc length = 33 cm
Central angle = 7Ï€/10 = 7* 3.14 / 10
=> radius = 33 cm / (7*3.14/10) = 33 cm / 2.198 = 15.01 cm, which rounded to the nearest whole is 15 cm.
Answer: 15 cm
