Is it true that the coordinate of the mass center of a convex polytope (constructed by n vertices) in a n-dimensional space is actually the average of all the vertices' coordinates? If so, how to prove it?
For example, say we have a convex polytope with vertices $(x_{11}, x_{12}, ..., x_{1n}), (x_{21}, x_{22}, ..., x_{2n}), ..., (x_{n1}, x_{n2}, ..., x_{nn})$, is it true that its mass center (mass is uniformly distributed over the polytope) is at $\frac{(x_{11}+ x_{21}+ ... +x_{n1})}{n}, \frac{(x_{12}+ x_{22}+ ... +x_{n2})}{n}, ..., \frac{(x_{1n}+ x_{2n}+ ... +x_{nn})}{n}$?
Thanks!