Answer:
1. 15.708
2. The radius would be half of the distance across the drain, or half of the diameter. Half of 3.8cm, or 3.8cm / 2 is 1.9cm.
The circumference is the distance around the drain, or if you trace the entire circle. The formula to find the circumference of a circle is 2 multiplied by pi and the radius of the circle, or C = 2(pi)r. Here, we just found the radius, so the circumference is 2 * pi (which is approximately 3.14) * 1.9cm, or approximately 11.9cm!
Explanation: