diff --git a/bangundatar/BangunDatar.java b/bangundatar/BangunDatar.java
new file mode 100644
index 0000000..33d35a6
--- /dev/null
+++ b/bangundatar/BangunDatar.java
@@ -0,0 +1,6 @@
+package bangundatar;
+
+public interface BangunDatar {
+    public double luas(int s1, int s2);
+    public double keliling(int s1, int s2);
+}
diff --git a/bangundatar/Lingkaran.java b/bangundatar/Lingkaran.java
new file mode 100644
index 0000000..1d5c037
--- /dev/null
+++ b/bangundatar/Lingkaran.java
@@ -0,0 +1,26 @@
+package bangundatar;
+
+public class Lingkaran implements BangunDatar {
+
+    private double pi = 3.1415;
+
+    Lingkaran(){}
+
+    @Override
+    public double luas(int s1, int s2) {
+        return 0;
+    }
+
+    @Override
+    public double keliling(int s1, int s2) {
+        return 0;
+    }
+
+    public double luas(int r){ //metode overload
+        return (pi * r * r);
+    }
+
+    public double keliling(int r){ //methode overload
+        return (2 * pi * r);
+    }
+}
diff --git a/bangundatar/Main.java b/bangundatar/Main.java
new file mode 100644
index 0000000..9f39bca
--- /dev/null
+++ b/bangundatar/Main.java
@@ -0,0 +1,70 @@
+package bangundatar;
+
+import java.util.Scanner;
+
+public class Main {
+    private static char pilihan;
+    private static Scanner scanner = new Scanner(System.in);
+
+    private static void main_menu(){
+        //pilihan menu
+        System.out.println("====================");
+        System.out.println("Hitung Luas dan Keliling :");
+        System.out.println("1. Persegi Panjang");
+        System.out.println("2. Segitiga Siku");
+        System.out.println("3. Lingkaran");
+        System.out.print("Masukan Menu : ");
+        pilihan = scanner.next().charAt(0);
+    }
+
+    public static void main(String[] args){
+        /*Kamus*/
+        PersegiPanjang opersegi;
+        SegitigaSiku osegitiga;
+        Lingkaran olingkaran;
+        int s1, s2, r;
+
+        opersegi = new PersegiPanjang();
+        osegitiga = new Segitiga();
+        olingkaran = new Lingkaran();
+
+        /*Program*/
+        //panggil metode
+        main_menu();
+
+        //kondisional untuk pilihan menu yang dimasukan
+        switch(pilihan){
+            case '1':{
+                System.out.print("Masukan panjang persegi: ");
+                s1 = scanner.nextInt();
+                System.out.print("Masukan lebar persegi: ");
+                s2 = scanner.nextInt();
+                System.out.println("Luas persegi panjang: " + opersegi.luas(s1,s2));
+                System.out.println("Keliling persegi panjang: " + opersegi.keliling(s1,s2));
+                break;
+            }
+            case '2':{
+                System.out.print("Masukan alas segitiga siku: ");
+                s1 = scanner.nextInt();
+                System.out.print("Masukan tinggi segitiga siku: ");
+                s2 = scanner.nextInt();
+                System.out.println("Luas segitiga: " + osegitiga.luas(s1,s2));
+                System.out.println("Keliling segitiga: " + osegitiga.keliling(s1,s2));
+                break;
+            }
+            case '3':{
+                System.out.print("Masukan jari-jari lingkaran: ");
+                r = scanner.nextInt();
+                System.out.println("Luas lingkaran: " + olingkaran.luas(r));
+                System.out.println("Keliling lingkaran: " + olingkaran.keliling(r));
+                break;
+            }
+            default :{
+                System.out.println("tidak ada pilihan");
+                break;
+            }
+
+        }
+
+    }
+}
diff --git a/bangundatar/PersegiPanjang.java b/bangundatar/PersegiPanjang.java
new file mode 100644
index 0000000..a2a761e
--- /dev/null
+++ b/bangundatar/PersegiPanjang.java
@@ -0,0 +1,17 @@
+package bangundatar;
+
+public class PersegiPanjang implements BangunDatar{
+
+    PersegiPanjang(){}
+
+
+    @Override
+    public double luas(int s1, int s2) {
+        return (s1 * s2);
+    }
+
+    @Override
+    public double keliling(int s1, int s2) {
+        return (2 * (s1 + s2));
+    }
+}
diff --git a/bangundatar/SegitigaSiku.java b/bangundatar/SegitigaSiku.java
new file mode 100644
index 0000000..dfeedb2
--- /dev/null
+++ b/bangundatar/SegitigaSiku.java
@@ -0,0 +1,16 @@
+package bangundatar;
+
+public class SegitigaSiku implements BangunDatar {
+
+    Segitiga(){}
+
+    @Override
+    public double luas(int s1, int s2) {
+        return (0.5 * s1 * s2);
+    }
+
+    @Override
+    public double keliling(int s1, int s2) {
+        return (s1 + s2 + Math.sqrt((s1*s1) + (s2*s2)));
+    }
+}