diff --git a/core/src/processing/core/PVector.java b/core/src/processing/core/PVector.java
index 5f9be436e..78209bb60 100644
--- a/core/src/processing/core/PVector.java
+++ b/core/src/processing/core/PVector.java
@@ -529,9 +529,10 @@ public class PVector {
    * @return the angle between the vectors
    */
   static public float angleBetween(PVector v1, PVector v2) {
-    float dot = v1.dot(v2);
-    float theta = (float) Math.acos(dot / (v1.mag() * v2.mag()));
-    return theta;
+    double dot = v1.x * v2.x + v1.y * v2.y + v1.z * v2.z;
+    double v1mag = Math.sqrt(v1.x * v1.x + v1.y * v1.y + v1.z * v1.z);
+    double v2mag = Math.sqrt(v2.x * v2.x + v2.y * v2.y + v2.z * v2.z);
+    return (float) Math.acos(dot / (v1mag * v2mag));
   }