Excercise 3.1 Class9
Question 1
How will you describe the position of a table lamp on your study table?
পঢ়াৰ টেবুলত থকা টেবুল লেম্পটোৰ অৱস্থান আপুনি কেনেকৈ বৰ্ণনা কৰিব?
Answer / উত্তৰ :
We describe the position by taking two reference lines (lengthwise and breadthwise) on the table.
সহজ ভাষাত:
টেবুলখনত দুটা দিশ (আগ-পিছ আৰু সোঁ-বাঁও) ধৰি লৈ লেম্পটো ক’ত আছে তাক বুজাব পাৰি।
🔹 Question 2
(Street plan question – NCERT based)
In a town, the position of a house is given with reference to two perpendicular roads.
Concept / সহজ বুজাব পৰা কথা :
- Two roads crossing each other at right angle act like x-axis and y-axis
- Their crossing point is the origin
- Distance from each road gives the coordinates
উত্তৰ (General):
ঘৰৰ অৱস্থান দুটা পথৰ পৰা দূৰত্ব ব্যৱহাৰ কৰি (x, y) আকাৰত লিখিব পাৰি।
🔹 Question 3
Name the point where the x-axis and y-axis intersect.
x-axis আৰু y-axis য’ত একেলগে মিলিত হয় সেই বিন্দুটোৰ নাম লিখা।
Answer / উত্তৰ :
The point is called Origin.
Coordinates of origin = (0, 0)
🔹 Question 4
What is the name of each part of the plane formed by x-axis and y-axis?
x-axis আৰু y-axis এ সমতলখনক ভাগ কৰা প্ৰতিটো অংশৰ নাম কি?
Answer / উত্তৰ :
Each part is called a Quadrant.
Total number of quadrants = 4
🔹 Question 5
Write the signs of coordinates in each quadrant.
প্ৰতিটো quadrant ত x আৰু y ৰ চিহ্ন লিখা।
Answer / উত্তৰ :
| Quadrant | x | y |
|---|---|---|
| I | + | + |
| II | − | + |
| III | − | − |
| IV | + | − |
📌 Origin does not lie in any quadrant.
📌 Origin কোনো quadrant ত নাথাকে।
🔹 Question 6
Name the quadrant in which the point (−3, 4) lies.
(−3, 4) বিন্দুটো কোন quadrant ত পৰে?
Solution / সমাধান :
- x is negative (−)
- y is positive (+)
👉 Second Quadrant (II)
🔹 Question 7
Name the quadrant in which the point (5, −2) lies.
(5, −2) বিন্দুটো কোন quadrant ত পৰে?
Solution / সমাধান :
- x is positive (+)
- y is negative (−)
👉 Fourth Quadrant (IV)
🔹 Question 8
On which axis does the point (4, 0) lie?
(4, 0) বিন্দুটো কোন axis ত থাকে?
Answer / উত্তৰ :
Since y = 0, the point lies on the x-axis.
🔹 Question 9
On which axis does the point (0, −6) lie?
(0, −6) বিন্দুটো কোন axis ত থাকে?
Answer / উত্তৰ :
Since x = 0, the point lies on the y-axis.
🌟 VERY IMPORTANT EXAM POINTS
✔ Coordinates are written as (x, y)
✔ First value → x-axis
✔ Second value → y-axis
✔ Axis points are not in any quadrant
❌ COMMON MISTAKES
❌ Writing (y, x)
❌ Wrong sign of quadrant
❌ Saying origin is in quadrant
🔁 Ultra-Quick Revision
- Meeting point → Origin
- 4 parts → Quadrants
- y = 0 → x-axis
- x = 0 → y-axis