Respuesta :

Remember that radius is half of the diameter (1/2 d)

10 * 2 = 20 

20 is the diameter. 

c
---   =  3.14               Get 'c' by itself by multiplying 20 to both sides
20

This eliminates the '20' in c/20 

c   =   3.14 (20)

Multiply. 

c = 62.8 

Your circumference is 62.8