#### Answer

All points on or within the cylinder centered on the y-axis with radius 3.

#### Work Step by Step

Start with our cylinder, $x^2 + z^2 \leq r^2$
Radius: $r= 3$
We have found the radius, but have not accounted for the bounds set by the inequality. We want to account for all points $r \leq 3$. This tells us we are working with all points on or within our cylinder.