diff --git a/doc/API.html b/doc/API.html
index a439505..7617f57 100644
--- a/doc/API.html
+++ b/doc/API.html
@@ -2628,6 +2628,9 @@ try {
       about <code>25</code> digits more than the precision required.
     </p>
     <p>The value can also be shortened to reduce the size of the source file.</p>
+    <p>To get the value of pi:</p>
+    <pre>
+pi = Decimal.acos(-1)</pre>