Answer:
 where
 where  denote arc lengths of two circles
 denote arc lengths of two circles
Step-by-step explanation:
Let  denote arc lengths of two circles,
 denote arc lengths of two circles,  denote corresponding radii and
 denote corresponding radii and 
 denote the corresponding central angles.
 denote the corresponding central angles.
So,
 and
 and 
This implies  and
 and 
As each circle has an arc where the measures of the corresponding central angles are the same, 

As radius of one circle is twice the radius of the other circle,

