diff --git a/src/ludus/prelude.ld b/src/ludus/prelude.ld
index 5afd761..4daa175 100644
--- a/src/ludus/prelude.ld
+++ b/src/ludus/prelude.ld
@@ -1266,6 +1266,7 @@ ns prelude {
 	atan/2
 	mod
 	square
+	sqrt
 	sum_of_squares
 	dist
 	random