diff --git a/w4/Triangle.java b/w4/Triangle.java
new file mode 100644
index 0000000..ac6e661
--- /dev/null
+++ b/w4/Triangle.java
@@ -0,0 +1,28 @@
+package com.shape;
+
+public class Triangle extends Shape {
+    private double sideA;
+    private double sideB;
+    private double sideC;
+
+    public Triangle(double sideA, double sideB, double sideC) {
+        if (!isValidTriangle(sideA, sideB, sideC)) {
+            throw new IllegalArgumentException("输入的三边无法构成三角形（必须满足三角形不等式）");
+        }
+        this.sideA = sideA;
+        this.sideB = sideB;
+        this.sideC = sideC;
+    }
+
+    // 判断是否能构成三角形（三角形不等式）
+    private boolean isValidTriangle(double a, double b, double c) {
+        return (a + b > c) && (a + c > b) && (b + c > a) && a > 0 && b > 0 && c > 0;
+    }
+
+    @Override
+    public double getArea() {
+        // 使用海伦公式计算三角形面积
+        double p = (sideA + sideB + sideC) / 2;   // 半周长
+        return Math.sqrt(p * (p - sideA) * (p - sideB) * (p - sideC));
+    }
+}
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