In a circle, the distance from the center of the circle to any point on the circumference is the radius of the circle. The radius of the circle is a constant number and does not change from one point to another.
This means that:
OC = OD = radius of circle
6x + 2 = 10x - 16
2+16 = 10x-6x
18 = 4x
x = 4.5
Therefore radius of circle can be calculated by getting length of either OC or OD as follows:
radius of circle = 6(4.5) + 2 = 28 units