diff --git a/w5/类图 b/w5/类图
new file mode 100644
index 0000000..259a8cf
--- /dev/null
+++ b/w5/类图
@@ -0,0 +1,29 @@
+classDiagram
+    class Shape {
+        <<abstract>>
+        +getArea() double
+    }
+    class Circle {
+        -radius: double
+        +Circle(radius: double)
+        +getArea() double
+    }
+    class Rectangle {
+        -width: double
+        -height: double
+        +Rectangle(width: double, height: double)
+        +getArea() double
+    }
+    class Triangle {
+        -base: double
+        -height: double
+        +Triangle(base: double, height: double)
+        +getArea() double
+    }
+    class ShapeUtil {
+        +printArea(Shape shape) void
+    }
+    Shape <|-- Circle
+    Shape <|-- Rectangle
+    Shape <|-- Triangle
+    ShapeUtil ..> Shape
\ No newline at end of file