Punktmasside süsteemi massikeskme koordinaadid

$${x_{mk} = \frac{1}{M}\sum_{i=1}^n m_i x_i \text{, }y_{mk} = \frac{1}{M}\sum_{i=1}^n m_i y_i \text{, }z_{mk} = \frac{1}{M}\sum_{i=1}^n m_i z_i}$$