diff --git a/lib/matrix.rb b/lib/matrix.rb
index b39973b..4f9708d 100644
--- a/lib/matrix.rb
+++ b/lib/matrix.rb
@@ -1999,6 +1999,29 @@ class Vector
     self / n
   end
 
+  #
+  # Returns an angle between vectors
+  #   Vector[1,0].angle_between(Vector[0,1])
+  #   # => 1.5707963267948966
+  #
+  def angle_between(v)
+    Vector.Raise ErrDimensionMismatch if size != v.size
+    raise ZeroVectorError, "Can't get angle of zero vector" if magnitude == 0 || v.magnitude == 0
+
+    Math.acos self.normalize.inner_product(v.normalize)
+  end
+
+  #
+  # Returns a projection to another vector
+  #   Vector[1,0].angle_between(Vector[0,1])
+  #   # => 1.5707963267948966
+  #
+  def projection_to(v)
+    Vector.Raise ErrDimensionMismatch if size != v.size
+
+    self.inner_product(v)/v.magnitude
+  end
+
   #--
   # CONVERTING
   #++
diff --git a/test/matrix/test_vector.rb b/test/matrix/test_vector.rb
index fa29496..d70bc36 100644
--- a/test/matrix/test_vector.rb
+++ b/test/matrix/test_vector.rb
@@ -169,4 +169,13 @@ class TestVector < Test::Unit::TestCase
     v = Vector[1, 0, 0].cross_product Vector[0, 1, 0]
     assert_equal(Vector[0, 0, 1], v)
   end
+
+  def test_angle_between
+    assert_in_epsilon(1.5707963267948966, Vector[1, 0].angle_between(Vector[0, 1]))
+  end
+
+  def test_projection_to
+    assert_equal(1.0, Vector[1, 1].projection_to(Vector[1,0]))
+    assert_in_epsilon(0.7071067811865475, Vector[0, 1].projection_to(Vector[1, 1]))
+  end
 end