diff --git a/src/TriangleChecker.java b/src/TriangleChecker.java
index 14f4841..963f9ec 100644
--- a/src/TriangleChecker.java
+++ b/src/TriangleChecker.java
@@ -1,9 +1,9 @@
 import java.util.Scanner;
 
 public class TriangleChecker {
-  
+
   public enum TriangleType {
-    NONE, 
+    NONE,
     NORMAL,
     ISOSCELES,  // Gleichschenklig
     EQUILATERAL // Gleichseitig
@@ -32,23 +32,34 @@ public class TriangleChecker {
     switch (type) {
       case NONE:
         System.out.println("Kein Dreieck");
-        break;        
+        break;
       case NORMAL:
         System.out.println("Dreieck");
-        break;        
+        break;
       case ISOSCELES:
         System.out.println("Gleichschenkliges Dreieck");
-        break;        
+        break;
       case EQUILATERAL:
         System.out.println("Gleichseitiges Dreieck");
-        break;        
+        break;
     }
   }
 
   // Analyse der Dreiecksart
   public static TriangleType checkTriangle(float a, float b, float c) {
+    if (triangleTheorem(a,b,c) ){
+      if(a==b && a==c){return TriangleType.EQUILATERAL;}
+      if(a==b||b==c||a==c){return TriangleType.ISOSCELES;}
+
+      return TriangleType.NORMAL;
+    }
     return TriangleType.NONE;
   }
 
-
+  public static boolean triangleTheorem(float a, float b, float c) {
+    if (a <= 0 || b <= 0 || c <= 0) {
+      return false;
+    }
+    return (a + b > c && b + c > a && a + c > b);
+  }
 }
\ No newline at end of file
diff --git a/test/TriangleCheckerTest.java b/test/TriangleCheckerTest.java
index 5c9ff57..8711bc5 100644
--- a/test/TriangleCheckerTest.java
+++ b/test/TriangleCheckerTest.java
@@ -16,6 +16,8 @@ public class TriangleCheckerTest {
 
         // Assert
         assertEquals(TriangleChecker.TriangleType.NORMAL, type);
+        assertEquals(TriangleChecker.TriangleType.EQUILATERAL, type);
+        assertEquals(TriangleChecker.TriangleType.ISOSCELES, type);
 
     }