What is the measure of the radius of s?

A diameter is a straight line that crosses a circle and the radius equals the half of this distance. So, in our case, the diameter would be YL which equals 12.2 adn the radius would be:

12.2 / 2 = 6.1

Though you could see it this way, there is still another way of finding the radius. The radius is a straght line that goes from the centre to any point of the circle, which is the same thing as saying that it is half of a diameter:

SG is a line going from the centre (S) to G, which is also equal to 6.1

Hope it helped,

BioTeacher101

sorry not knowing about that