diff --git a/lib/msun/man/hypot.3 b/lib/msun/man/hypot.3
index 978b390b940..083e1387b33 100644
--- a/lib/msun/man/hypot.3
+++ b/lib/msun/man/hypot.3
@@ -129,3 +129,12 @@ function and a
 function
 appeared in
 .At v7 .
+.Sh STANDARDS
+The
+.Fn hypot ,
+.Fn hypotf ,
+.Fn cabs ,
+and
+.Fn cabsf
+functions conform to
+.St -isoC-99 .