The formula of an area of a circle:
[tex]A=\pi r^2[/tex]
We have R = 6mm and r = 5 mm.
Substitute:
[tex]A_1=\pi(6^2)=36\pi\ mmm^2\\\\A_2=\pi(5^2)=25\pi\ mm^2[/tex]
The ratio:
[tex]\dfrac{A_1}{A_2}=\dfrac{36\pi}{25\pi}=\dfrac{36}{25}[/tex]
Answer: 36 : 25
