NCERT Solutions for Class 9 Maths Unit 3
Coordinate Geometry Class 9
Unit 3 Coordinate Geometry Exercise 3.1, 3.2, 3.3 Solutions
Introduction to Coordinate Geometry
A system of geometry where the position of points on the plane is described using an ordered pair of numbers.
Recall that a plane is a flat surface that goes on forever in both directions. If we were to place a point on the plane, coordinate geometry gives us a way to describe exactly where it is by using two numbers.
What are coordinates?
Grid with rows and columns labelled. To introduce the idea, consider the grid on the right. The columns of the grid are lettered A,B,C etc. The rows are numbered 1,2,3 etc from the top. We can see that the X is in box D3; that is, column D, row 3.
D and 3 are called the coordinates of the box. It has two parts: the row and the column. There are many boxes in each row and many boxes in each column. But by having both we can find one single box, where the row and column intersect.