# Statement(s) > [!NOTE] Statement 1 (Formula for collinearity of distinct points) > Let $\mathbf{x},\mathbf{y},\mathbf{z}\in \mathbb{R}^n,$ then they are collinear iff $d(\mathbf{x},\mathbf{y})=d(\mathbf{x},\mathbf{z})+d(\mathbf{z},\mathbf{y})$up to permuting $\mathbf{x},\mathbf{y}$ and $\mathbf{z}.$ **Moreover**: if $\mathbf{x},\mathbf{y},\mathbf{z}$ are distinct and $\mathbf{z}=\lambda_{1}\mathbf{x}+\lambda_{2}\mathbf{y}$ with $\lambda_{1}+\lambda_{2}=1$ then $|\lambda_{1}|:|\lambda_{2}|=d(z,y):d(z,x)$ \* Diagram here \* # Proof(s) **Proof of statement 1:** $\blacksquare$ # Application(s) **Consequences**: **Examples**: # Bibliography