DefinitionPath Length- Length along a (curved) path in a plane is measured by this. It computes by using the Euclidean distance formula and integrating over the parameterization of the curves. Arc length is useful for evaluating the distance traveled in physics, engineering, or wherever you would like to measure path distance. Applications include finding the work done by a force, analysis of curves in space, etc. The above formula is used in calculus to find the arc length of a function \( y = f(x)\), \( a <= x <= b \) where \( a \) & \( b \) are the x-coordinates.