The distance of a point from the y-axis is called its x-coordinate, or abscissa.
The distance of a point from the x-axis is called its y-coordinate, or ordinate.
The coordinates of a point on the x-axis are of the form (x, 0), and of a point on the y-axis are of the form (0, y).
The two axes, x axis and y axis, divide the plane into four regions called quadrants. In first quadrant both x and y are positive. In second quadrant x is negative and y is positive. In third quadrant both x and y are negative. And in fourth quadrant x is positive and y is negative.
The distance between the points P(x1, y1) and Q(x2, y2) is given by the distance formula:
The distance of a point P(x, y) from the origin is .
The coordinates of the point P(x, y) which divides the line segment joining the points A(x1, y1) and B(x2, y2) internally in the ratio m1 : m2 are given by . This is known as Section Formula.
The mid-point of the line segment joining the points P(x1, y1) and Q(x2, y2) is .
The area of the triangle formed by the points (x1, y1), (x2, y2) and (x3, y3) is the numerical value of the expression