- In geometry, a Cartesian coordinate system (UK: /kɑːrˈtiːzjən/, US: /kɑːrˈtiːʒən/) in a plane is a coordinate system that specifies each point uniquely by a pair of real numbers called coordinates, which are the signed distances to the point from two fixed perpendicular oriented lines, called coordinate lines, coordinate axes or just axes (plural of axis) of the system. The point where they meet is called the origin and has (0, 0) as coordinates.
- Mali (Wikipedia)
Mali, officially the Republic of Mali, is a landlocked country in West Africa. Mali is the eighth-largest country in Africa, with an area of over 1,241,238 square kilometres (479,245 sq mi). The country is bordered to the north by Algeria, to the east by Niger, to the northwest by Mauritania, to the south by Burkina Faso and Ivory Coast, and to the west by Guinea and Senegal. The population of Mali is 21.9 million, 67% of which was estimated to be under the age of 25 in 2017. Its capital and largest city is Bamako. The country has 13 official languages, of which Bambara is the most commonly spoken.