diff --git a/src/OpenTK/Math/MathHelper.cs b/src/OpenTK/Math/MathHelper.cs
index b073a9aa..535fcd99 100644
--- a/src/OpenTK/Math/MathHelper.cs
+++ b/src/OpenTK/Math/MathHelper.cs
@@ -32,7 +32,7 @@ namespace OpenTK
         public const float PiOver3 = Pi / 3;
 
         /// <summary>
-        /// Definesthe value of  Pi divided by four as a <see cref="System.Single"/>.
+        /// Defines the value of  Pi divided by four as a <see cref="System.Single"/>.
         /// </summary>
         public const float PiOver4 = Pi / 4;