diff --git a/w4/Circle.java b/w4/Circle.java
new file mode 100644
index 0000000..584068d
--- /dev/null
+++ b/w4/Circle.java
@@ -0,0 +1,12 @@
+public class Circle extends Shape {
+    private double radius;
+
+    public Circle(double radius) {
+        this.radius = radius;
+    }
+
+    @Override
+    public double getArea() {
+        return Math.PI * radius * radius;
+    }
+}
\ No newline at end of file
diff --git a/w4/Rectangle.java b/w4/Rectangle.java
new file mode 100644
index 0000000..90cb267
--- /dev/null
+++ b/w4/Rectangle.java
@@ -0,0 +1,14 @@
+public class Rectangle extends Shape {
+    private double width;
+    private double height;
+
+    public Rectangle(double width, double height) {
+        this.width = width;
+        this.height = height;
+    }
+
+    @Override
+    public double getArea() {
+        return width * height;
+    }
+}
\ No newline at end of file
diff --git a/w4/Shape.java b/w4/Shape.java
new file mode 100644
index 0000000..e1a96c5
--- /dev/null
+++ b/w4/Shape.java
@@ -0,0 +1,3 @@
+public abstract class Shape {
+    public abstract double getArea();
+}
\ No newline at end of file
diff --git a/w4/ShapeTest.java b/w4/ShapeTest.java
new file mode 100644
index 0000000..136a171
--- /dev/null
+++ b/w4/ShapeTest.java
@@ -0,0 +1,18 @@
+public class ShapeTest {
+    public static void main(String[] args) {
+        // 创建各个图形对象
+        Shape c = new Circle(5);
+        Shape r = new Rectangle(4,6);
+        Shape t = new Triangle(3,4);
+
+        //统一调用工具打印面积
+        System.out.print("圆形：");
+        ShapeUtil.printArea(c);
+
+        System.out.print("矩形：");
+        ShapeUtil.printArea(r);
+
+        System.out.print("三角形：");
+        ShapeUtil.printArea(t);
+    }
+}
\ No newline at end of file
diff --git a/w4/ShapeUtil.java b/w4/ShapeUtil.java
new file mode 100644
index 0000000..37e32e3
--- /dev/null
+++ b/w4/ShapeUtil.java
@@ -0,0 +1,5 @@
+public class ShapeUtil {
+    public static void printArea(Shape shape){
+        System.out.println("图形面积：" + shape.getArea());
+    }
+}
\ No newline at end of file