Learning target: You understand a coordinate system in a plane. You know how to enter points in a coordinate system and read the coordinates of entered points. You are capable of detecting entries that are obviously wrong - for example wrong sign. You know the difference between a Cartesian and a polar coordinate system in a plane.

This chapter deals with the "Where", more precisely, with the method of determining a location. For this, you need a starting point, units of measure, and a reasonable connection of both: the coordinate system.

Two digressions deal with the topics:

A summary containing examples rounds off the chapter.