← Back to Articles List

Coordinate Geometry

Distance between two points
d=(x2x1)2+(y2y1)2 

Problems:
1. Find the distance between the points P(0, 0) and Q(sinθ,cosθ)    Ans: 1
2. Find the distance between the points (1, 1) and (sinθ+1,cosθ+1)    Ans: 1
3. The point A(m2, 9) is equidistant from both the axes. Find the value of m.    Ans: ±3 
4. Distance between origin and the point (p, 4) is 5 units. Find the value of p where p > 0.   Ans: 3
5. Show that the points A(-5, 0), B(5, 0), C(5, 5), and D(-5, 5) are the four vertices of a rectangle.  Hint: opposite sides are equal, angles are right angle.
6. P(x, y) is equidistant from the points A(4, 3) and C(-3, - 2). Show that 7x + 5y = 6.  [C.B. 2023]
7. From the point P(x, y), the distance of y-axis is equal to the distance of P from the point D(4, 3). Show that, y2 -6y - 8x + 25 = 0. [Dhaka Board 2021]

Midpoint
M=(x1+x22,y1+y22) 

Problems:
1. The vertices of a triangle ABC are A(2, -1), B(-4, 2), and C(2, 5). Find the length of the median AD.   Ans: 3213  
2. PQRS is a parallelogram where P(8, 3), Q(3, 8), R(-2, 3). Find the coordinates of the point S.  Ans: (3, -2)  Hint: diagonals of a parallelogram bisect each other.

Slop of a line
m=y2y1x2x1 

Problems:
1. Slope of a line is -4 and value of y-intercept is 2. Write the equation of the line.
2. If AB || CD for the points A(x, y), B(1, 2), C(2, 1), and D(-x, -y); prove that x - y + 1 = 0 [M.B. 2023]
3. If P(m2+2, 3m), Q(4, 8), and R(7, 5) points are colinear, find the value of m. [C.B. 2021]
4. Show that, the connecting straight line between points (3, -5) and (6, 4) form an acute angle with the positive side of x-axis. [Rajshahi Board 2023]


Slope of a line perpendicular to the with slope m is:
1m ; negative reciprocal of the original line's slope.

Equation of a line through a point (x​1​, y​1​):
yy1=m(xx1) 

Problems:
1. Find of equation of a line with gradient -2 that passes through the point (-5, 5).
2. The straight line y = -3x + 2 passes through the point P(t, 8) and intersects at A and B on x-axis and y-axis respectively. Determine the value of t. Then find out the equation of straight line whose gradient is 3 and passes through P. [Dinajpur Board 2022]

Find intersetion point from given equations:
1. Determine the area of the triangle formed by three equation: y = x + 7, y = -x + 5, and y = 3. [Sylhet Board 2022]   
2. Determine the ratio of the area of the triangles formed by the lines L1 : 3x + 8y = 25 and L2 : 9x + 2y = 31 with axes. [Cumilla Board 2022, Jashore Board 2022]
3. A(-4, 4), B(6, 4), C(6, -7), and D(4, -7) are four vertices of a quadrilateral. Determine the area of that portion of quadrilateral ABCD which resides in the fourth quadrant. [Rajshahi Board 2023]

406,

1. A is the point (-1, -5) and B is the point (3, 3).
    Find the equation of the line perpendicular to AB which passes throught the midpoint of AB.
                       [ 4024/22/M/J/21 ]
2. The line L crosses the graph of y = 1 + 2x at x = 2 and x = 5
    Find the equation of L.
                                         [ 4024/22/M/J/19 ]
3. A line with gradient 13 crosses the graph of y=1+2x when x = 1 and when x = k.
    Find k.
                                         [ 4024/22/M/J/19 ]
4. Line L is perpendicular to the line 2y = x + 4.
    Line L passes through the point (1, 8).
    Show that the equation of line L is y = 10 - 2x

5. Use an algebraic method to find the coordinates of the point of intersection of the lines 2y = x + 4 and y = 23 - 2x.

6. A is the point (-1, 3) and B is the point (5, 5).
    (i) Calculate the length AB.
    (ii) Find the equation of the line perpendicular to AB that passes through the midpoint of AB.
                                 [ 4024/21/M/J/18 ]
7. (a) The points (4, -3) and (0, 5) lie on the line L.
         Find the equation of line L.
   (b) The line M is parallel to line L and passes through the point (-2, 3).
         Find the equation of line M.
                                 [ 4024/21/O/N/17 ]

1. P is the point (3, -3) and Q is the point (1,5)
    (a) Calculate the length of PQ.
    (b) Find the equation of the perpendicular bisector of PQ.                                  [ 4024/21/M/J/22 ]

2. D is a point (4, 6) and E is the point (e, e).
    (a) The length of DE is 20 
          Form an equation in e and solve it to find the possible coordinates of E.
          Show your working.
    (b) F is the point (-f, 5f).
         The gradient of the perpendicular bisector of DF is 32 
         (i) Find the value of f.
         (ii) The equation of the perpendicular bisector of DF is 2y = 3x + k .
              Find the value of k .                                                                                     4024/22/M/J/22 ]

3. A is the point (-2, 3) and B is the point (4, 5).
    (a) Find the coordinates of the midpoint of AB.
    (b) Show that the equation of line AB is 3y = x + 11.
    (c) Find the equation of the perpendicular bisector of line AB.                            4024/21/O/N/21 ]

4024/21/O/N/23
1. a) The equation of line L is 4y = x - 5 .
       i)  Find the gradient of line L.
      ii)  Find the coordinate of the point where line L crosses the y-axis.
   b) A is the point (4, 5) and B is the point (-2, 8).
       i)  Find the length of line AB.
      ii)  Find the equation of line AB. Give your answer in the form y = mx + c .

4024/22/O/N/23
1. The equation of line P is y = 4x - 3 .
    Line L is perpendicular to line P .
    Line L passes through the point (6, 4).

     Find the coordinates of the point where line L crosses the x-axis.

4024/21/O/N/22
1.
  P is the point (r, 4) and Q is the point (t, u).

  The midpoint of line PQ is (1, 3).
  The gradient of line PQ is 14 

  Find the value of each of r, t and u.