Another small improvements;

src/net/hypki/testjava/figures/Area.java

@@ -0,0 +1,5 @@
+package net.hypki.testjava.figures;
+
+public interface Area {
+	public double computeArea();
+}

src/net/hypki/testjava/figures/Triangle.java

@@ -0,0 +1,50 @@
+package net.hypki.testjava.figures;
+
+public class Triangle implements Area {
+	
+	private double a;
+	
+	private double h;
+	
+	private String color = "blue";
+
+	public Triangle(double a, double b) {
+		setA(a);
+		setH(b);
+	}
+	
+	@Override
+	public String toString() {
+		return "Triangle area = " + computeArea();
+	}
+
+	@Override
+	public double computeArea() {
+		return 0.5 * getA() * getH();
+	}
+
+	public double getA() {
+		return a;
+	}
+
+	public void setA(double a) {
+		this.a = a;
+	}
+
+	public double getH() {
+		return h;
+	}
+
+	public void setH(double h) {
+		this.h = h;
+	}
+
+	public String getColor() {
+		return color;
+	}
+
+	public void setColor(String color) {
+		this.color = color;
+	}
+
+}

src/net/hypki/testjava/main/Main.java

@@ -1,9 +1,11 @@
 package net.hypki.testjava.main;
 
+import net.hypki.testjava.figures.Area;
 import net.hypki.testjava.figures.Circle;
 import net.hypki.testjava.figures.Figure;
 import net.hypki.testjava.figures.Rectangle;
 import net.hypki.testjava.figures.Square;
+import net.hypki.testjava.figures.Triangle;
 
 public class Main {
 
@@ -24,6 +26,15 @@ public class Main {
 		
 		Circle c = new Circle(3);
 		System.out.println(c);
+		
+		Triangle t = new Triangle(1, 2);
+		System.out.println(t.getColor());
+		
+		Area a = new Triangle(4, 10);
+		System.out.println(a);
+		
+		
+		System.out.println(((Triangle) a).getColor());
 	}
 
 }