Well-structured ICSE S Chand Maths Class 9 Solutions Chapter 20 Coordinates and Graphs of Simultaneous Linear Equations Ex 20(A) facilitate a deeper understanding of mathematical principles.

## S Chand Class 9 ICSE Maths Solutions Chapter 20 Coordinates and Graphs of Simultaneous Linear Equations Ex 20(A)

Question 1.

Plot the following points on a graph paper using the same pair of axes and the same scale for each one.

(i) (0,18)

(ii) (2, 9)

(iii) (5, 8)

(iv) (7, 0)

(v) (5, -8)

(vi) (10,-16)

(Vii) (8, -14)

(viii) (3,-11)

(ix) (-5, 6)

(x) (-15, 4)

(xi) (-20, 8)

(xii) (-9, 5)

(xiii) (-5, 8)

(xiv) (0, 7)

(xv) (-8, -15)

(xvi) (-12, -7)

(xvii) (-10, -11)

(xviii) (-8, 0)

(xix) (-4, 15)

(XX) (7, -6)

Solution:

The points given, have been plotted on the graph given below :

Question 2.

The coordinates of the three vertices of a rectangle are given. By plotting the given points, find in each case, the co-ordinates of the fourth vertex.

(i) A (4, 2), B (-2, 2) and D (4, -2);

(ii) B (10, 4), C (0, 4) and D (0, -2).

Solution:

(i) The points A (4, 2), B (-2, 2) and D (4, -2) have been plotted. To complete the rectangle, the point C will be its fourth vertex whose co-ordinates are (-2, -2).

(ii) The point B (10, 4), C (0, 4) and D (0, -2) have been plotted on the graph. To complete the rectangle the point A will be its fourth point whose co-ordinates are (10, -2).

Question 3.

A (-2, 4), C (4, 10) and D (-2, 10) are the vertices of a square ABCD. Use graphical method to find the coordinates of the fourth vertex B. Also, find

(i) the coordinates of the mid-point of BC,

(ii) the coordinates of the mid-point of CD and

(iii) the coordinates of the point of intersection of the diagonals of the square ABCD.

Solution:

Plot the points A (-2, 4), C (4, 10) and D (-2, 10) on the graph and join them and complete the square

(i) The fourth point is B whose vertices are (4, 4).

(ii) The mid-point of BC will be P whose cocordinates will be (4, 7).

(iii) The mid-point of CD will be Q whose cocordinates will be (1, 10).

(iv) Its diagonals AC and BD intersect each other at O whose co-ordinates will be (1, 7).