Respuesta :

claire33p7xpgf

Answer:

3 : 7

Step-by-step explanation:

Let the radii be 3x, 7x.

Circumference = 2πr, where r = radius

Thus, ratio of circumference:

2 × π × 3x : 2 × π × 7x

= 3 : 7

( as 2, π and x get cancelled out)