Introduction to Quadrants in the Coordinate PlaneDate: 02/05/2004 at 13:36:18 From: Jon Subject: geometry What is a quadrant? How do you find it? I had to identify 9 ordered pairs on a graph. Now I need to also name the quadrant each one is in. Date: 02/05/2004 at 16:22:37 From: Doctor Rob Subject: Re: geometry Thanks for writing to Ask Dr. Math, Jon! In a rectangular coordinate system, the x- and y-axes divide the plane into four regions. These are called quadrants. They are numbered, often using Roman numerals: y ^ II | I | <------+------>x | III | IV | Quadrant I is also called the first quadrant, and so on. Note that all points in each of the four quadrants share the same x and y values in terms of positive or negative. For example, if both numbers are positive, the point will be in the first quadrant. In general: I: x > 0, y > 0 or x positive, y positive. II: x < 0, y > 0 or x negative, y positive. III: x < 0, y < 0 or x negative, y negative. IV: x > 0, y < 0 or x positive, y negative. If either coordinate is 0, the point will not be in a quadrant, but will lie on an axis. All points with y = 0 are on the x-axis, and all points with x = 0 are on the y-axis. Note that the origin (0,0) is the only point on both axes. Feel free to write again if I can help further. - Doctor Rob, The Math Forum http://mathforum.org/dr.math/ |
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