>>10895071To understand if it's inside or outside you look at the equation. For example first you draw the z^2=x^2 + y^2 which gives you the lines you drew. Now if you have the z^2 <= x^2 + y^2 you just pick any point on any line and think, if I put a smaller z the inequality is also true but the point is closer to the plane, so you know that the outside is a part of it.
In these cases you can notice that where z^2 <= something things closer to the plane above and below belong and things further away don't. In the cases z <= something the bottom belongs and the top doesn't.
