diff --git a/source/reference/operator/centerSphere.txt b/source/reference/operator/centerSphere.txt
index 9afc27f9185..041a3cc9c87 100644
--- a/source/reference/operator/centerSphere.txt
+++ b/source/reference/operator/centerSphere.txt
@@ -17,7 +17,7 @@ $centerSphere
 
    .. code-block:: javascript
 
-      db.collection.find( { loc: { $centerSphere: { [0,0], 10 / 3959 } } } )
+      db.collection.find( { loc: { $within: { $centerSphere: { [0,0], 10 / 3959 } } } } )
 
    This query will return all documents within a 10 mile radius of
    ``[0,0]`` using a spherical geometry to calculate distances.