NCERT Solutions for Class 9 Maths Chapter 3: Coordinate Geometry

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The NCERT Solutions for class 9 Maths Chapter 3 Coordinate Geometry have been provided in the article below. Coordinate Geometry deals with geometrical problems solved using coordinate systems and points.

Class 9 Maths Chapter 3 Coodinate Geometry belongs to Unit 3 Coordinate Geometry having a weightage of 04 in the Class 9 Maths Examination. NCERT Solutions for Class 9 Maths for Chapter 3 cover the following important concepts: 

Download: NCERT Solutions for Class 9 Maths Chapter 3 pdf


NCERT Solutions for Class 9 Maths Chapter 3

The Chapter 3 Class 9 Maths are given below:

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Important Topics in Class 9 Maths Chapter 3 Coordinate Geometry

Important Topics in Class 9 Maths Chapter 3 Coordinate Geometry are elaborated below: 

  • Distance Formula of Coordinate Geometry

Distance formula of coordinate geometry, derived from the Pythagoras Theorem, is used to determime the distance between any 2 given points. These points are usually located on an x-y coordinate plane. Distance Formula of coordinate geometry can be written as, AB = √[(x2-x1)²+(y2-y1)²]

Example: Consider coordinate A (-4,0) and B (0,3). With the given coordinates, determine the distance between these two points.

Solution: Considering the coordinates ofA = (-4,0) = (x1, y1)
And the coordinates of B = (0,3) = (x2,y2)
Now by using Distance Formula, we can get,
AB = √{(x2-x1)²+(y2-y1)²} = √{[0-(-4)]²+ (3-0)²}
= √(4²+3²)} = √(16+9) = √25
= 5 units

  • Section Formula of Coordinate Geometry

Section Formula helps to determine the coordinates of a point that assists division of the line joining two points in a ratio. The equation occurs either internally or externally.

Section Formula of Coordinate Geometry can be classified into two parts:

  1. Internal Section Formula: \(P(x,y) = (\frac{mx_2+nx_1}{m+n} , \frac{my_2+ny_1}{m+n})\)
  2. External Section Formula: \(P(x,y) = (\frac{mx_2-nx_1}{m-n} , \frac{my_2-ny_1}{m-n})\)
  • Ordinate 

Ordinate represents the coordinate values present on the y-axis on a coordinate system. It is the second component of an ordered pair.

Example: What will be the abscissa and ordinate of a point with coordinates (8,12)?

Solution: The coordinates of (8, 12) are:
Abscissa: 12
And, Ordinate: 8

  • Quadrant

Quadrants are the parts that form when two coordinate axes of a plane tend to intersect with one another at an angle of 90 degree. The intersection these two lines experience is called a point of reference. 

Example: Highlight the quadrants where coordinate points (-2,7) take place? 

Solution: (-2,7) falls in the second quadrant. Here, the value of the x axis becomes negative. 

  • Cartesian System

Cartesian System, derived from the number line, is used to label points in a plane. The cartesian form is derived from the number line. It has two perpendicular lines named as X-axis and Y-axis.

Important points to remember in Cartesian System:

  • The point of intersection of both the axes is called the origin. It has coordinates (0, 0).
  • An infinite number of points can be plotted on a cartesian coordinate plane.
  • Points that fall on any of the number lines don’t belong to any quadrant.

NCERT Solutions for Class 9 Maths Chapter 3 Exercises:

The detailed solutions for all the NCERT Solutions for Coordinate Geometry under different exercises are:

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CBSE X Related Questions

  • 1.
    For any natural number n, \( 5^n \) ends with the digit :

      • 0
      • 5
      • 3
      • 2

    • 2.
      Assertion (A) : If probability of happening of an event is \(0.2p\), \(p>0\), then \(p\) can't be more than 5.
      Reason (R) : \(P(\bar{E}) = 1 - P(E)\) for an event \(E\).

        • Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
        • Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
        • Assertion (A) is true, but Reason (R) is false.
        • Assertion (A) is false, but Reason (R) is true.

      • 3.
        If \(PQ\) and \(PR\) are tangents to the circle with centre \(O\) and radius \(4 \text{ cm}\) such that \(\angle QPR = 90^{\circ}\), then the length \(OP\) is

          • \(4 \text{ cm}\)
          • \(4\sqrt{2} \text{ cm}\)
          • \(8 \text{ cm}\)
          • \(2\sqrt{2} \text{ cm}\)

        • 4.
          PQ is tangent to a circle with centre O. If \(OQ = a\), \(OP = a + 2\) and \(PQ = 2b\), then relation between \(a\) and \(b\) is

            • \(a^2 + (a + 2)^2 = (2b)^2\)
            • \(b^2 = a + 4\)
            • \(2a^2 + 1 = b^2\)
            • \(b^2 = a + 1\)

          • 5.
            An ice-cream cone of radius \(r\) and height \(h\) is completely filled by two spherical scoops of ice-cream. If radius of each spherical scoop is \(\frac{r}{2}\), then \(h : 2r\) equals

              • \(1 : 8\)
              • \(1 : 2\)
              • \(1 : 1\)
              • \(2 : 1\)

            • 6.
              The graph of \(y = f(x)\) is given. The number of zeroes of \(f(x)\) is :

                • 0
                • 1
                • 3
                • 2

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