Show that the two marked curves have the same length



One curve is half the circumference of a circle with radius \(1\).
Its length is \(\pi\).
The second curve consists of two circular arcs that meet in a point.
Each of these arcs is half the circumference of a circle with radius \(\frac{1}{2}\).
The length of such an arc is \( \frac{\pi}{2}\).
The total length of the second curve is then also \(\pi\).