The circumference of two circles are 12\pi and 36\pi. Find

The circumference of two circles are $12\pi$ and $36\pi$. Find the ratio of the areas of the circles.
a) $1:3$
b) $1:9$
c) $3:4$
d) $2:5$
You can still ask an expert for help

• Questions are typically answered in as fast as 30 minutes

Solve your problem for the price of one coffee

• Math expert for every subject
• Pay only if we can solve it

vefibiongedogn7z
Step 1
We know that circumference of circle $=2\pi r$
For first circle $2\pi r=12\pi$
$⇒r=6$
For second circle, $2\pi r=36\pi$
$⇒r=18$
Step 2
Area of the circle $=\pi {r}^{2}$
For first circle
Area
$=36\pi$
For second circle
Area
$=324\pi$
Ratio of the area of circle is
$36\pi :324\pi$
$=1:9$
Itence the answe is $1:9$