@@ -0,0 +1,508 @@
+package pravvich;%0A%0Apublic class Triangle %7B%0A%09public Point a;%0A%09public Point b;%0A%09public Point c;%0A%0A%09public Triangle(Point a, Point b, Point c) %0A%09%7B%0A%09%09this.a = a;%0A%09%09this.b = b;%0A%09%09this.c = c;%0A%09%7D%0A%0A%09%09%0A%09//calculate the triangle area%0A%09public double area(Point a, Point b, Point c) %0A%09%7B%0A%09%09double result;%0A%09%09double semiper = ((a.distanseTo(b))*(a.distanseTo(c))*(b.distanseTo(c)) )/2;%0A%09%09result = Math.sqrt( semiper*(semiper - a.distanseTo(b))*(semiper - a.distanseTo(c))*(semiper - b.distanseTo(c) ));%0A%09%09return result;%0A%09%7D%0A%7D

add chapter_001\lesson_3\src\main\java\ru\pravvich\Triangle.java