Section formula
The section formula in coordinate geometry is a fundamental mathematical tool used to calculate the coordinates of a point that divides the line segment joining two given points, either internally or externally, in a specified ratio m:n.[1] This formula bridges algebraic expressions with geometric positions on a plane, enabling precise determination of point locations along a line.[2] For internal division, where the point lies between the two endpoints A(x_1, y_1) and B(x_2, y_2), the coordinates of the dividing point P are given byP\left( \frac{m x_2 + n x_1}{m + n}, \frac{m y_2 + n y_1}{m + n} \right). [3] In contrast, for external division, where the point lies outside the segment, the coordinates are
P\left( \frac{m x_2 - n x_1}{m - n}, \frac{m y_2 - n y_1}{m - n} \right), assuming m \neq n.[1] A special case is the midpoint formula, derived when m:n = 1:1, yielding P\left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right).[2] The section formula finds extensive applications in analytic geometry, such as computing centroids of triangles, verifying collinearity of points, and solving problems in vector geometry and computer graphics for interpolation between coordinates.[3] It also aids in determining the ratio in which a given point divides a line segment, enhancing problem-solving in fields like physics for position vectors and engineering for spatial calculations.[1]