Improved precision of MicroInch constant in Length. Fixed test.

Author: angularsen

Src/UnitsNet/Length.cs

@@ -28,8 +28,9 @@ namespace UnitsNet
     /// </summary>
     public struct Length : IComparable, IComparable<Length>
     {
-        private const double MilsToMetersRatio = 2.54E-5;
         public readonly double Meters;
+        private const double MilsToMetersRatio = 2.54E-5;
+        private const double MicroInchToMeterRatio = 2.54E-8;
 
         /// <summary>
         ///     Enforce static methods for creation.
@@ -93,7 +94,7 @@ public double Nanometers
 
         public double Microinch
         {
-            get { return Meters * 39370078.7; }
+            get { return Meters / MicroInchToMeterRatio; }
         }
 
         public double Mil
@@ -183,7 +184,7 @@ public static Length FromNanometers(double nm)
 
         public static Length FromMicroinches(double mi)
         {
-            return FromMeters(mi / 39370078.7);
+            return FromMeters(mi * MicroInchToMeterRatio);
         }
 
         public static Length FromMils(double mils)

Tests/LengthTests.cs

@@ -25,7 +25,7 @@ public void MetersToDistanceUnits()
             Assert.AreEqual(1.09361, meter.Yards, Delta);
             Assert.AreEqual(3.28084, meter.Feet, Delta);
             Assert.AreEqual(39.3701, meter.Inches, Delta);
-            Assert.AreEqual(39370078.7, meter.Microinch, Delta);
+            Assert.AreEqual(39370078.74015748, meter.Microinch, Delta);
             Assert.AreEqual(39370.07874015, meter.Mil, Delta);
         }