Class 9 · Chapter 1

Orienting Yourself: The Use of Coordinates

Cartesian plane, plotting points, distance and midpoint.

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Ganita Manjari · Class 9 (2026-27)
Tip: NCERT updated the syllabus for 2026-27. The links above open the latest edition on the official portal — chapter titles and numbering may differ from the notes shown here.
Detailed theory
Descartes' breakthrough: turn geometry into algebra. Each point in the plane corresponds uniquely to an ordered pair (x,y)(x, y).
Key concepts & formulas
01
Cartesian plane: two perpendicular axes at origin (0,0)(0,0).
02
Point P(x,y)P(x, y): xx horizontal, yy vertical.
03
Quadrants I (+,+)(+,+), II (−,+)(-,+), III (−,−)(-,-), IV (+,−)(+,-).
04
Distance formula: d=(x2−x1)2+(y2−y1)2d = \sqrt{(x_2-x_1)^2 + (y_2-y_1)^2}.
05
Midpoint: M=(x1+x22,y1+y22)M = \left(\dfrac{x_1+x_2}{2}, \dfrac{y_1+y_2}{2}\right).
Gyaan Maths — CBSE Class 6-12, built for board-toppers.
v1.1 · Sept 2026