methemetikcs but anyways yea I don't understand this I'm any way shape or form.

Answer:
C
Step-by-step explanation:
The center of the large circle is Center D. It has can area of 900 pi square units. This means that according to the formula of the area of circle,
[tex]\pi {r}^{2} [/tex]
Since Point D is the center of the large circle, by definition of a circle, diameter, and radius.
The area of the 3 small circles are equal so this means that the radius,any physical characteristics of the 3 circles are equal.
This means that each diameter of the 3 circles equally divide the diameter of the large circle into 3 equal parts.
This means Circle C diameter is 20.
Circumference is
[tex]\pi d[/tex]
The diameter is 20 so the circumference of Circle C is
[tex]20\pi[/tex]