NCERT Solutions for Class 9th Maths Chapter 1 In-text Questions — The 2-d Cartesian Coordinate System
Book page 7 Updated on2026-09-08
Q1.
Copy Fig. 1.4 and mark S and Q in your diagram. Mark any point P in Quadrant I and any point R in Quadrant III, and write down their coordinates.
Answer
S (3, −5) and Q (−5, 3) are fixed by the question. P and R may be chosen freely — here P (4, 2) and R (−4, −3).
S and Q are given; P and R are choices. The dashed paths show how each point is reached from O: first the horizontal shift, then the vertical one.
S (3, −5): from O go 3 right, then 5 down → Quadrant IV
Q (−5, 3): from O go 5 left, then 3 up → Quadrant II
P = (4, 2) — both coordinates positive → Quadrant I
R = (−4, −3) — both coordinates negative → Quadrant III
Why it happens: The order in the pair is what makes the marking unambiguous. Look at S (3, −5) and Q (−5, 3): they use the same two numbers, 3 and −5, yet they are different points in different quadrants. The first entry is always the horizontal shift and the second always the vertical one — that agreement is what lets one pair of numbers name one point, and only one.
Try This: Your P and R will not match the ones above, and that is fine — the question says any point. Check your own choice by its signs alone: (+, +) must be Quadrant I and (−, −) must be Quadrant III. If you picked P (4, 0) you have made a mistake: that point lies on the x-axis, not in Quadrant I.