The radius is [tex]\frac{1}{2}[/tex] (half) the diameter.
Since you know the diameter = 22 cm, [tex]\frac{1}{2}[/tex] of 22 = 11. So the radius = 11 cm
You could also use equations: (d = diameter r = radius)
d = 2r ---> [tex]r=\frac{d}{2}[/tex] And plug in what you know
