Answer:
C≈13.19 cm
Explanation:
The circumference of a circle equation is C=2πr. Use the circumference of a circle equation and substitute the radius for 2.1. Then, you can calculate 2·π·2.1. The answer to the circumference of a circle is about 13.1946. Finally, you round to the nearsest hundredths place, so the answer is about 13.19 cm.
Work
C=2πr
C= 2·π·2.1
C≈13.1946≈13.19