| Basics of Coordinate Metrology Unit 2: Coordinate systems in a plane | Step 2 of 5 |
| The importance of two-dimensional approach in mathematics comes from the fact that its history was related to problems in land surveying. In addition, a plane has an advantage compared with space: In a plane, "ideal" mathematical objects come very close to our possibilities of action: We can draw points, distances, circles, triangles and other geometrical figures, study the length relationships using sketches and drawings, discover connections (for example the law of Pythagoras or the fact that the sum of angles in a triangle is 180°), in a word: do math. A plane is a flat surface like a piece of paper or a table top that extends in all directions. No area on it can be distinguished from the other, (it has no mountains nor valleys) in any direction. |  Law of Pythagoras: |