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 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 distance between the points P(x₁, y₁) and Q(x₂, y₂) is called Distance formula.

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 called Section formula.

The area of the triangle formed by the points (x₁, y₁), (x₂, y₂) and (x₃, y₃) = 1/2[x₁(y₂ - y₃) + x₂(y₃ - y₁) + x₃(y₁ - y₂)]