PREPARING Become a MATIZEN What is Math Planet ? A Crash Course on      Algebra A Crash Course on      Geometry   EXPLORING Advanced Math Topic Customized Lessons SAT & ACT Reviews   INTERACTING Math Games Discussion Forum Math Live! Chat   COLLECTING Math Search MATIZEN Qualifi-      -cation Test Acknowledgements The Creatures Behind      the Math Planet        ©1998 ThinkQuest        team 16284    All rights reserved

Chapter 4: Coordinate Geometry

# The Basics

Everything in this world is made of points, and we can locate a specific place with points. That’s why the coordinate system is developed. Coordinate system is used throughout life from air trafficking to ocean navigation. Coordinate geometry is the starting point for a person to know the coordinate system. Coordinate geometry is so important that many advanced math topics have to be solved using the coordinate system.

Before you dive into the world of coordinate geometry, you have to know a few terms that are used to describe the coordinate system. The coordinate system is in a plane made of infinite of points. For every point in the plane, there is a pair of number that is used to describe the point. The first number is called the x-coordinate or abscissa. It is used to tell the horizontal position of the point. The second number is called the y-coordinate or ordinate. It is used to tell the vertical position of the point. The point with position (0,0) is the center of the coordinate system. By extending the point horizontally and vertically, you get a cross that is used to determine the positions of the other points on the plane. The cross also divides the plane into four sections or quadrants. We name them from first to fourth starting with the one on the top right corner and turning counterclockwise. Both x and y coordinates in first quadrant are positive. X coordinate in second quadrant is negative while Y coordinate is positive. Both x and y coordinates in third quadrant are negative. Y coordinate in fourth quadrant is negative while X coordinate is positive.

You can also jump to the chapter of your choice by using the drop-down list at below.