English: location triangle by Alfred Weber. This is a triangle, whose apexes are 2 raw material sites and 1 market. And the distances between each apexes and the factory are defined as ${\displaystyle d_{1}}$, ${\displaystyle d_{2}}$, and ${\displaystyle d_{3}}$. The weights of raw material 1, 2 and the production are ${\displaystyle W_{1}}$, ${\displaystyle W_{2}}$, and ${\displaystyle W_{3}}$. If the transport cost is minimised, the factory should be located where ${\displaystyle d_{1}W_{1}+d_{2}W_{2}+d_{3}W_{3}}$ is the minimum possible.