This rock known as balanced rock sits on a thin spike of rock in a canyon in idaho. explain the that keep the rock balanced on its tiny pedestal

Now, suppose you have a more common figure, like a square, and you want to balance it over a pencil for example.

When you put the square over the pencil, you want that the point where the square touches the pencil is right in the middle of one of the faces of the square. This is because, in this situation, you know that the mass is evenly distributed over all sides now, and none side of the square is pulling down with more force than another side.

Now, this is the same with this rock, the mass is evenly distributed around the contact point, so no side has more force downwards than another side, then all the forces are canceled, and if there are no forces acting on the rock, it will remain in place.