Question

Using Java

Create the class RightTriangle which is a triangle with one of its angles equal to 90º – a “right angle”.

• Its constructor will require the lengths only of its two legs. It will then calculate the length of the third side (its “hypotenuse”) using the Pythagorean Theorem:

a² + b² = c².

• This class will have no instance variables itself, so it will need to set the appropriate variables in its parent class, Triangle.
• It will inherit equals from its parent class
• You also should enhance the String returned from the toString method of its parent class to identify this as a right triangle
• It will inherit getNumberOfSides, calculatePerimeter, and calculateArea from its parent.

You also should recalculate the hypotenuse every time one of the two legs changes. How would you do this?

In your main method,  create a right triangle with legs of length 3 and 4, use toString to print the lengths of all sides, the perimeter, and the area. Do the same using legs of length 5 and 12.

Triangle.java

public class Triangle{

private double length1, length2, length3;
  
public Triangle(double len1, double len2, double len3)
{
this.length1 = len1;
this.length2 = len2;
this.length3 = len3;
}

public double getLength1() {
return length1;
}

public void setLength1(double length1) {
this.length1 = length1;
}

public double getLength2() {
return length2;
}

public void setLength2(double length2) {
this.length2 = length2;
}

public double getLength3() {
return length3;
}

public void setLength3(double length3) {
this.length3 = length3;
}
  
@Override
public int getNumberOfSides(){ return 3; }
  
@Override
public String toString()
{
return("Number of sides: " + getNumberOfSides() + ", Side1: " + String.format("%.2f", getLength1())
+ ", Side2: " + String.format("%.2f", getLength2())
+ ", Side3: " + String.format("%.2f", getLength3())
+ ", Area: " + String.format("%.2f", super.getArea())
+ ", Perimeter: " + String.format("%.2f", super.getPerimeter()));
}

@Override
public boolean equals(Object object) {
if(object instanceof Triangle)
{
return(getLength1() == ((Triangle) object).getLength1()
&& getLength2() == ((Triangle) object).getLength2()
&& getLength3() == ((Triangle) object).getLength3());
}
else
return false;
}

@Override
public void calculatePerimeter() {
setPerimeter(length1 + length2 + length3);
}

@Override
public void calculateArea() {
double p = super.getPerimeter() / 2;
double area = Math.sqrt(p * (p - length1) * (p - length2) * (p - length3));
super.setArea(area);
}
}

Answer 1

public class Triangle{

private double length1, length2, length3;

public Triangle(double len1, double len2, double len3)

{

this.length1 = len1;

this.length2 = len2;

this.length3 = len3;

}

public double getLength1() {

return length1;

}

public void setLength1(double length1) {

this.length1 = length1;

}

public double getLength2() {

return length2;

}

public void setLength2(double length2) {

this.length2 = length2;

}

public double getLength3() {

return length3;

}

public void setLength3(double length3) {

this.length3 = length3;

}

@Override

public int getNumberOfSides(){ return 3; }

@Override

public String toString()

{

return("Number of sides: " + getNumberOfSides() + ", Side1: " + String.format("%.2f", getLength1())

+ ", Side2: " + String.format("%.2f", getLength2())

+ ", Side3: " + String.format("%.2f", getLength3())

+ ", Area: " + String.format("%.2f", super.getArea())

+ ", Perimeter: " + String.format("%.2f", super.getPerimeter()));

}

@Override

public boolean equals(Object object) {

if(object instanceof Triangle)

{

return(getLength1() == ((Triangle) object).getLength1()

&& getLength2() == ((Triangle) object).getLength2()

&& getLength3() == ((Triangle) object).getLength3());

}

else

return false;

}

@Override

public void calculatePerimeter() {

setPerimeter(length1 + length2 + length3);

}

@Override

public void calculateArea() {

double p = super.getPerimeter() / 2;

double area = Math.sqrt(p * (p - length1) * (p - length2) * (p - length3));

super.setArea(area);

}

}