The ordered pair of the number which is used to indicate the position of a point on a grid is known as the coordinates of a point. Co-ordinates axes are the horizontal and vertical number lines which intersect each other perpendicularly at the point O.

The reflection of a geometrical figure means the formation of the image of the figure after reflecting the figure about the line of reflection.

When each vertex of a geometrical figure is rotated through a certain angle in a certain direction about a given centre of rotation the figure is said to be rotated through the same centre of rotation. When the coordinates of the image of a point is rotated through 90 and 180 in anticlockwise and clockwise directions about the centre of rotation at origin.