Answer:
4 Units
Explanation:
A diameter is a line that passes through the center of a circle thus dividing it into two semicircles. A radius is half of a diameter, a line drawn from any part of the circumference of the circle to the center of the circle.
Given that the diameter of circle S is 30 units, the radius of the circle CS
= 30/2 units
= 15 unit
If DS = 9 units and from the circle, we know that
DC + DS = CS
DC = 15 - 9
= 6 Units
If the diameter of circle R is 20 units then the radius DR
= 20/2 units
= 10 units
but CR + DC = DR
Hence CR = 10 units - 6 units
= 4 Units