If the radius of circle is tripled, by how many times does its circumference increase?

How many times does its area increase?

Suppose we have a circle of radius r.
Then its circumference = $2\mathrm{\pi r}$
And its area = ${\mathrm{\pi r}}^2$
Now when the radius of circle gets tripled i.e the radius of the circle will be 3r.
Then its circumference = $2\mathrm{\pi }\times 3\mathrm{r} = 6\mathrm{\pi r}$
And its area = $\mathrm{\pi }{\left(3\mathrm{r}\right)}^2 = 9{\mathrm{\pi r}}^2$
So, $\frac{\mathrm{circumference} \mathrm{of} \mathrm{circle} \mathrm{of} \mathrm{radius} 3\mathrm{r}}{\mathrm{circumference} \mathrm{of} \mathrm{circle} \mathrm{of} \mathrm{radius} \mathrm{r}} = \frac{6\mathrm{\pi r}}{2\mathrm{\pi r}} = 3$
$\Rightarrow \mathrm{circumference} \mathrm{of} \mathrm{circle} \mathrm{of} \mathrm{radius} 3\mathrm{r} = 3\times \mathrm{circumference} \mathrm{of} \mathrm{circle} \mathrm{of} \mathrm{radius} \mathrm{r}$
Therefore the circumference will become 3 times when the radius of the circle gets tripled.

Also, $\frac{\mathrm{area} \mathrm{of} \mathrm{circle} \mathrm{of} \mathrm{radius} 3\mathrm{r}}{\mathrm{area} \mathrm{of} \mathrm{circle} \mathrm{of} \mathrm{radius} \mathrm{r}} = \frac{9{\mathrm{\pi r}}^2}{{\mathrm{\pi r}}^2} = 9$
$\Rightarrow \mathrm{area} \mathrm{of} \mathrm{circle} \mathrm{of} \mathrm{radius} 3\mathrm{r} = 9\times \mathrm{area} \mathrm{of} \mathrm{circle} \mathrm{of} \mathrm{radius} \mathrm{r}$
Therefore the area of circle will become 9 times when the radius of the circle gets tripled.