A line on a plane can be represented by coordinates of the two end points p1 and p2 as p1(x1, y1) and p2(x2, y2).

A super class **Plane** is defined to represent a line and a subclass **Circle** to find the length of the radius and the area of circle by using the required data members of super class.

Some of the members of both the classes are given below:

**Class name:** Plane**Data members/instance variables:**

x1: to store the x-coordinate of the first end point.

y1: to store the y-coordinate of the first end point.**Member functions/methods:**

Plane(int x, int y): parameterized constructor to assign the data members x1 = x and y1 = y.

void show(): to display the coordinates.

**Class name:** Circle**Data members/instance variables:**

x2: to store the x-coordinate of the second end point.

y2: to store the y-coordinate of the second end point.

radius: double variable to store the radius of the circle.

area: double variable to store the area of the circle.**Member functions/methods:**

Circle(…): parameterized constructor to assign values to data members of both the classes.

void findRadius(): to calculate the length of radius using the formula:

(√ ((x2 – x1)^{2} + (y2 – y1)^{2})) / 2

assuming that x1, x2, y1, y2 are the coordinates of the two ends of the diameter of a circle.

void findArea(): to find the area of circle using formula: πr^{2}. The value of pie (π) is 22 / 7 or 3.14.

void show(): to display both the coordinates along with the length of the radius and area of the circle.

Specify the class **Plane** giving details of the constructor and void show(). Using the concept of inheritance, specify the class **Circle** giving details of the constructor, void findRadius(), void findArea() and void show().

**The main function and algorithm need not be written.**

```
class Plane{
protected int x1;
protected int y1;
public Plane(int x, int y){
x1 = x;
y1 = y;
}
public void show(){
System.out.println("x1: " + x1);
System.out.println("y1: " + y1);
}
}
class Circle extends Plane{
protected int x2;
protected int y2;
protected double radius;
protected double area;
public Circle(int a, int b, int c, int d){
super(a, b);
x2 = c;
y2 = d;
radius = 0.0;
area = 0.0;
}
public void findRadius(){
radius = Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2)) / 2;
}
public void findArea(){
area = 3.14 * radius * radius;
}
public void show(){
super.show();
System.out.println("x2: " + x2);
System.out.println("y2: " + y2);
System.out.println("Radius: " + radius);
System.out.println("Area: " + area);
}
}
```