Center of gravity of symmetrical objects:

The center of gravity of objects which have symmetrical shapes can be found in their geometry. 

The center of gravity of a uniform rod:

The center of gravity of a uniform rod lies at a point where it is balanced. This balance point is its middle point G.

Center of gravity of a uniform square or a rectangular sheet:

The center of gravity of a uniform square or a rectangular sheet is the point of intersection of its diagonals.

Center of gravity of a uniform circular disc:

The center of gravity of a uniform circular disc is its center.

Center of gravity of a solid sphere or hollow sphere:

The center of gravity of a solid sphere or hollow sphere is the center of the spheres.

Center of gravity of a uniform circular ring:

The center of gravity of a uniform circular ring is the center of the ring.

Center of gravity of a uniform solid or hollow cylinder:

The center of gravity of a uniform solid or a hollow cylinder is the middle point on its axis.