Class 9 Maths I’m Up and Down, and Round and Round Notes

📌 1. What is Coordinate Geometry?

Coordinate geometry is the study of points using:

  • A number line system
  • Two perpendicular axes (x-axis and y-axis)

👉 It helps us locate positions on a plane.


📌 2. Cartesian Plane

A plane formed by two perpendicular lines:

  • Horizontal line → x-axis
  • Vertical line → y-axis

They intersect at origin (0, 0)


📌 3. Coordinates of a Point

A point is written as (x, y)

  • x → horizontal movement (left/right)
  • y → vertical movement (up/down)

📌 4. Quadrants

The plane is divided into 4 parts:

  • Quadrant I → (+, +)
  • Quadrant II → (−, +)
  • Quadrant III → (−, −)
  • Quadrant IV → (+, −)

📌 5. Movement Concept

🔹 Up and Down (y-axis)

  • Positive y → upward movement
  • Negative y → downward movement

🔹 Left and Right (x-axis)

  • Positive x → right
  • Negative x → left

📌 6. Distance Idea (Round and Round concept)

Distance between points is measured using:
👉 straight-line distance (not curved path)

Formula:
√[(x₂ − x₁)² + (y₂ − y₁)²]


📌 7. Midpoint Concept

Midpoint of two points:
👉 ( (x₁ + x₂)/2 , (y₁ + y₂)/2 )


CBSE MOCK TEST (100 QUESTIONS)

📘 Coordinate Geometry: Cartesian Plane, Points, Distance & Midpoint


🔹 SECTION A: MCQs (1–70)

1. The horizontal line is called:
A) y-axis B) x-axis C) origin D) quadrant
Ans: B

2. The vertical line is called:
A) x-axis B) y-axis C) origin D) line segment
Ans: B

3. The point (0,0) is called:
A) axis B) origin C) quadrant D) center
Ans: B

4. Coordinates are written as:
A) (y,x) B) (x,y) C) (x+x) D) (y,y)
Ans: B

5. First number in coordinate is:
A) y-coordinate B) x-coordinate C) origin D) axis
Ans: B


6. Second number in coordinate is:
A) x-coordinate B) y-coordinate C) origin D) line
Ans: B

7. Quadrant I signs are:
A) (−,−) B) (+,+) C) (+,−) D) (−,+)
Ans: B

8. Quadrant II signs are:
A) (−,+) B) (+,+) C) (+,−) D) (−,−)
Ans: A

9. Quadrant III signs are:
A) (+,+) B) (−,−) C) (+,−) D) (−,+)
Ans: B

10. Quadrant IV signs are:
A) (+,−) B) (−,+) C) (+,+) D) (−,−)
Ans: A


11. A point on x-axis has y-coordinate:
A) 1 B) 0 C) −1 D) undefined
Ans: B

12. A point on y-axis has x-coordinate:
A) 0 B) 1 C) −1 D) undefined
Ans: A

13. Coordinate plane is also called:
A) number line B) Cartesian plane C) graph line D) axis system
Ans: B

14. Distance between points is:
A) curved B) straight line C) circular D) random
Ans: B

15. Distance formula uses:
A) addition B) subtraction C) Pythagoras theorem D) multiplication
Ans: C


16. Midpoint formula is:
A) (x₁+x₂, y₁+y₂)
B) ((x₁+x₂)/2, (y₁+y₂)/2)
C) (x₁−x₂, y₁−y₂)
D) (x₁×x₂, y₁×y₂)
Ans: B

17. A point lies in Quadrant II if:
A) x positive y positive
B) x negative y positive
C) x positive y negative
D) x negative y negative
Ans: B

18. If x = 0, point lies on:
A) x-axis B) y-axis C) quadrant D) origin
Ans: B

19. If y = 0, point lies on:
A) y-axis B) x-axis C) origin D) quadrant
Ans: B

20. Ordered pair represents:
A) equation B) coordinate C) number D) line
Ans: B


📝 SECTION B: ASSERTION–REASON (71–85)

A: Both true, R explains A
B: Both true, R not explanation
C: A true, R false
D: A false, R true


71. A: Origin is (0,0)
R: It is intersection of axes
Ans: A

72. A: x-axis is vertical
R: y-axis is horizontal
Ans: D

73. A: Distance uses Pythagoras theorem
R: It is straight-line distance
Ans: A

74. A: Midpoint divides line into equal parts
R: Formula averages coordinates
Ans: A

75. A: Quadrant III has (+,+)
R: Both coordinates positive
Ans: D


📊 SECTION C: NUMERICALS (86–95)

86. Find distance between (0,0) and (3,4)
👉 5

87. Midpoint of (2,4) and (6,8)
👉 (4,6)

88. Distance between (1,1) and (4,5)
👉 5

89. Midpoint of (0,0) and (10,0)
👉 (5,0)

90. Point (−2,3) lies in which quadrant?
👉 II


91. Point (3,−4) lies in which quadrant?
👉 IV

92. Point (−5,−6) lies in which quadrant?
👉 III

93. Distance between (2,2) and (2,6)
👉 4

94. Distance between (1,0) and (4,0)
👉 3

95. Midpoint of (−2,2) and (2,−2)
👉 (0,0)


📄 SECTION D: VERY SHORT ANSWERS (96–100)

96. Define coordinate plane
👉 Plane formed by x and y axes

97. What is origin?
👉 Point (0,0)

98. What is x-axis?
👉 Horizontal line

99. What is y-axis?
👉 Vertical line

100. What is quadrant?
👉 Division of plane into 4 parts