# RD Sharma Solutions for Class 9 Maths Chapter 11: Coordinate Geometry

The concept of coordinate geometry has been developed by describing the position or the location of various points with respect to the two axes (x and y axes) when 2D coordinate geometry is considered. This concept was first brought to light by French mathematician René Descartes. The method was developed for describing curves and lines by equations. The plane is called the Cartesian Coordinate Plane, and the points are called Cartesian Coordinates.

We can perform several things in coordinate geometry. Those are, Determining the distance between two points. Finding the slope of a line segment Defining the equations of curves, circles and ellipses Finding the area and perimeter of a polygon defined by the coordinates

These are the applications of the Coordinate Geometry that would be taught in the higher classes, and these form the basis for various other concepts as well. Thus, this introductory chapter on Coordinate Geometry is very important to understand

In coordinate geometry, coordinates are always represented on the coordinate plane. 2 scales always run across the plane. Those are the 'X' axis and 'Y' axis. 'X' axis is horizontal, and the 'Y' axis is vertical. The point where each axis intersects is called "Origin". Each axis divides the plane of coordinate into 4 quadrants. The first quadrant has all positive values, and the second quadrant has X-axis negative and Y-axis positive, the third has X-axis and Y-axis both negative values, and the fourth axis has X-axis positive and Y-axis negative. All the coordinates are located on the plane by measuring from the origin. On the X-axis, the values towards the Right of origin are positive and towards the left are negative. The values above the origin on the Y-axis are positive, and the values below are negative. Coordinates are always written in brackets.

If a coordinate is taken, i.e. (5,7). The first number 5 represents the X-axis while the 7 represents the Y-axis. As both 5 & 7 are positive so they will be going right and above the origin, i.e., the first quadrant, as mentioned earlier. Coordinate (-5, -7) lies on the third quadrant and so on.