Question 1: C = 2(pi)r and C = d(pi) are the formulas for finding the C. Circumference of a circle.
Question 2: The radius of the circle in the example has not been provided in the context. If more information about the circle is available, please share it so I can assist you further.
Question 3: Similarly, the circumference of the circle in the example cannot be determined without additional information. If you provide the radius or diameter, I can help calculate the circumference.