Answer:
18:19
Step-by-step explanation:
Given that,
The radius of circle A = 9 cm
The diameter of circle B = 19 cm
We know that,
Radius = diameter/2
The radius of circle B = 19/2 cm
The circumference of circle A is :
[tex]C_A=2\pi r_A[/tex] ....(1)
And that of circle B is :
[tex]C_B=2\pi r_B[/tex] ....(2)
Dividing equation (1) and (2) :
[tex]\dfrac{C_A}{C_B}=\dfrac{2\pi r_A}{2\pi r_B}\\\\=\dfrac{r_A}{r_B}\\\\=\dfrac{9}{\dfrac{19}{2}}\\\\\dfrac{C_A}{C_B}=\dfrac{18}{19}[/tex]
Hence, the ratio of circumferences of Circle A and Circle B is 18:19.
