diff --git a/src/main/java/pythagoras/d/Plane.java b/src/main/java/pythagoras/d/Plane.java
index ab7d8c7..f56e6ac 100644
--- a/src/main/java/pythagoras/d/Plane.java
+++ b/src/main/java/pythagoras/d/Plane.java
@@ -189,7 +189,7 @@ public class Plane implements IPlane, Serializable
     @Override // from IPlane
     public boolean intersection (IRay3 ray, Vector3 result) {
         double distance = distance(ray);
-        if (Float.isNaN(distance) || distance < 0f) {
+        if (Double.isNaN(distance) || distance < 0f) {
             return false;
         } else {
             ray.origin().addScaled(ray.direction(), distance, result);
diff --git a/src/main/java/pythagoras/d/Quaternion.java b/src/main/java/pythagoras/d/Quaternion.java
index 2e68c44..bc00eab 100644
--- a/src/main/java/pythagoras/d/Quaternion.java
+++ b/src/main/java/pythagoras/d/Quaternion.java
@@ -308,7 +308,7 @@ public class Quaternion implements IQuaternion, Serializable
 
     @Override // from IQuaternion
     public boolean hasNaN () {
-        return Float.isNaN(x) || Float.isNaN(y) || Float.isNaN(z) || Float.isNaN(w);
+        return Double.isNaN(x) || Double.isNaN(y) || Double.isNaN(z) || Double.isNaN(w);
     }
 
     @Override // from IQuaternion