--- a/master/painting.html	Fri May 18 12:21:07 2012 +1000
+++ b/master/painting.html	Fri May 18 12:39:15 2012 +1000
@@ -702,12 +702,29 @@
 
 <p>The ratio of miter length (distance between the outer tip and
 the inner corner of the miter) to <a>'stroke-width'</a> is directly
-related to the angle (theta) between the segments in user space by the
+related to the angle <var>θ</var> between the segments in user space by the
 formula:</p>
 
-<pre>
-miterLength / stroke-width = 1 / sin ( theta / 2 )
-</pre>
+<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">
+  <mrow>
+    <mfrac>
+      <mi>miterLength</mi>
+      <mi>stroke-width</mi>
+    </mfrac>
+    <mo>=</mo>
+    <mfrac>
+      <mn>1</mn>
+      <mrow>
+        <mi>sin</mi>
+        <mo>&#x2061;</mo>
+        <mfrac>
+          <mi>θ</mi>
+          <mn>2</mn>
+        </mfrac>
+      </mrow>
+    </mfrac>
+  </mrow>
+</math>
 
 <p>For example, a miter limit of 1.414 converts miters to bevels for
 theta less than 90 degrees, a limit of 4.0 converts them for theta less