how can we measure a length of a curved line

Procedure to Measure the Length of a Curved Line

• Take a non-stretchable string or a thread and tie a knot at one of its ends.
• Place the knotted end of the thread at one end of the curved line.
• Holding the thread steadily with your fingers, and stretch it along the curved line until you reach the other end.
• Now make a mark on the thread where it reaches the other end.
• Finally, place the thread along a metre scale and measure the length between the knot and the marked point.
• This gives the length of the curved line.