Let
x---------> my favorite number
we know that
(x+9)/15=3/5------> 5*(x+9)=15*3-----> divide by 5 both sides----> (x+9)=3*3
x+9=9------> x=0
therefore
the answer is
My favorite number is 0
I believe the answer is X=15
Answer: 
Step-by-step explanation:
Given
The diameter of a circle is 
So, the radius is 
The circumference is given by 
Insert the values

Thus, the circumference of the circle is