I don't understand......anyone please explain.

Question

I am quite new in Java. I read some tutorial and I don't understand somthing
There are two file. The first one named Particle.java
public Particle(double x, double y)
      this(x,y,1);
   public Particle(double x, double y, double mass)
      this.x = x; this.y = y; this.mass = mass;
   public double getWeight()
      return 9.8*mass;
   public double distanceFromOrigin()
      return Math.sqrt(x*x + y*y);
}The other file named MyApplication.java
public class MyApplication
   public static void main(String[] args)
      /* Need an instance of class Particle - a particle object;
      assign it to the variable a which is of type Particle. */
      Particle a = new Particle(1.0,1.0);
      System.out.println("Distance of particle a from origin = " + a.distanceFromOrigin());
      System.out.println("Mass of particle a = " + a.mass);
      Particle b = new Particle();
      b.x = 2.0;
      b.y = 3.0;
      b.mass = 3;
      System.out.println("Distance of particle b from origin = " + b.distanceFromOrigin());
      System.out.println("Mass of particle b = " + b.mass);
      System.out.println("Weight of particle b = " + b.getWeight());
}When run the program. This is the result that I get
Distance of particle a from origin = 1.4142135623730951
Mass of particle a = 1.0
Distance of particle b from origin = 3.605551275463989
Mass of particle b = 3.0
Weight of particle b =29.400000000000002
My question is I do not understand why Distance of particle b from origin = 3.605551275463989 Anyone please explain how to get this value.......please

Answer 1

You call this line...
Math.sqrt(x*x + y*y);
x = 2, y = 3
so..
Math.sqrt(4 + 9) = Math.sqrt(13)
the square root of 13 is 3.6055...