diff --git a/maths/arc_length.py b/maths/arc_length.py
index 9e87ca38cc7d..4c518f321dc7 100644
--- a/maths/arc_length.py
+++ b/maths/arc_length.py
@@ -7,6 +7,8 @@ def arc_length(angle: int, radius: int) -> float:
     3.9269908169872414
     >>> arc_length(120, 15)
     31.415926535897928
+    >>> arc_length(90, 10)
+    15.707963267948966
     """
     return 2 * pi * radius * (angle / 360)