$\"\"$

The point masses are $\"\"$ , $\"\"$ and $\"\"$

The point is the line $\"\"$ .

The moment about origin of the mass is $\"\"$ .

Substutute $\"\"$ , $\"\"$ and $\"\"$ and $\"\"$ in the th moment of the origin.

$\"\"$

The moment of origin is $\"\"$ .

$\"\"$

The center of th mass system is $\"\"$ .

Then substitute $\"\"$ , $\"\"$ and $\"\"$ and $\"\"$ in the mass system.

$\"\"$

The center of mass is $\"\"$ .

$\"\"$

The moment of origin is $\"\"$ .

The center of mass is $\"\"$ .