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Coordinate Geometry
Chapter summary, hard words and model exam answers for ICSE Class 9 Hindi.
Free online summary and notes (ICSE Class 9 Hindi). Read it here, no PDF download needed.
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Maths · ICSE Class 9
Summary
Two perpendicular number lines form the Cartesian plane. The horizontal line is the x-axis and the vertical line is the y-axis. They meet at the origin, written as (0, 0).
A point is written as (x, y). The first number, x, is the abscissa. The second number, y, is the ordinate. The order matters: (2, 5) and (5, 2) are usually different points.
Start from the origin. Move right for positive x or left for negative x. Then move up for positive y or down for negative y. Mark the point at the final position.
The axes divide the plane into four quadrants. Quadrant I has (+, +), Quadrant II has (-, +), Quadrant III has (-, -), and Quadrant IV has (+, -).
On the x-axis, y = 0. On the y-axis, x = 0. The origin is the only point that lies on both axes.
When sides are parallel to axes, lengths can be found by subtracting coordinates. This helps to find the area of rectangles, squares and right triangles on graph paper.
Hard words & meanings
| Cartesian plane | The plane formed by the x-axis and y-axis |
| origin | The point where the axes meet, written as (0, 0) |
| abscissa | The x-coordinate of a point |
| ordinate | The y-coordinate of a point |
| quadrant | One of the four regions made by the coordinate axes |
| collinear | Points lying on the same straight line |
| ordered pair | A pair of numbers written in order as (x, y) |
Model exam answers, grammar & audio
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