diff --git a/design-patterns/linear-chaining/index.md b/design-patterns/linear-chaining/index.md
index 31ae3a7..b9cd305 100644
--- a/design-patterns/linear-chaining/index.md
+++ b/design-patterns/linear-chaining/index.md
@@ -66,7 +66,7 @@ task calculate_circle_area {
   }
 
   command <<<
-    bc -l <<< "2 * ~{pi} * ~{radius}"
+    bc -l <<< "~{pi} * ~{radius} ^ 2"
   >>>
 
   output {