The circumference of any circle is (pi) x (the diameter of the circle).
The problem gives you both numbers, so all you have to do is multiply them.
Circumference = (pi) x (diameter) = (3.14) x (21cm) = <em>65.94 cm .</em>
Answer:

Step-by-step explanation:
Use these formulas

Now solve

Answer:
11.C
12.B
Step by step explanation: