What is rectifiable curves?

Rectifiable curves are curves in a Euclidean space that have a finite length. This means that the total distance along the curve can be measured and is finite when calculated using the concept of line integrals. Rectifiable curves can be approximated by a series of straight line segments, and they are important in various fields of mathematics, including calculus and geometric measure theory. A classic example of a rectifiable curve is a smooth curve like a circle or a straight line segment.