8.import java.util.*;
public class Problem8
{
    public static void main(String[] args)
    {
        Scanner console = new Scanner(System.in);
        System.out.print("Input a value for a: ");
        double a = console.nextDouble();
        System.out.print("Input a value for b: ");
        double b = console.nextDouble();
        System.out.print("Input a value for c: ");
        double c = console.nextDouble();
        discriminant(a, b, c);
        double xvertex = -(b/(2*a));
        double discr = discriminant(a, b, c)/2*a;
        double x1 = xvertex + discr;
        double x2 = xvertex - discr;
        System.out.println("Your X1 Value is " + x1);
        System.out.println("Your X2 Value is " + x2);
    }
    public static double discriminant(double a, double b, double c)
    {
        return(Math.sqrt(b*b-4*a*c));
    }
}
10.import java.util.*;
public class problem10
{
    public static void main(String[] args)
    {
        double area = 0.0;
        System.out.print("Input your radius to calculate your area: ");
        Scanner console = new Scanner(System.in);
        int radius = console.nextInt();
        area = calculation(radius);
        System.out.println("Your area for your circle is: " + area);
    }
    public static double calculation(int radius)
    {
        double area = Math.PI*Math.pow(radius, 2);
        return area;
    }
}
12.import java.util.*;
public class problem12
{
    public static void main(String[] args)
    {
        Scanner console=new Scanner(System.in);
        System.out.print("Input your base number");
        double base = console.nextDouble();
        System.out.print("Input your exponet");
        int exponent = console.nextInt();
        double scientific=calculation(base, exponent);
        System.out.println("Your number is:"+ scientific);
    }
    public static double calculation(double base, int exponent)
    {
        double scientific = base*Math.pow(10, exponent);
        return scientific;


    }
}
14.import java.util.*;
public class problem14
{
    public static void main(String [] args)
    {
        Scanner pikachu = new Scanner(System.in);
        System.out.print("Input your radius");
        double radius = pikachu.nextDouble();
        System.out.print("Input your height");
        double height= pikachu.nextDouble();
        double surface=cylinderSurfaceArea(radius, height);
        System.out.println("Your surfacearea of the is:"+ surface);
    }
    public static double cylinderSurfaceArea(double radius, double height)
    {
        double surface=2*Math.PI*Math.pow(radius,2)+2*Math.PI*radius*height;
        return surface;
    }
}
16.import java.util.*;
public class problem16
{
    public static void main(String [] args)
    {
        Scanner pikachu = new Scanner(System.in);
        System.out.print("Input your first triangle side");
        double side1 = pikachu.nextDouble();
        System.out.print("Input your second triangle side");
        double side2 = pikachu.nextDouble();
        System.out.print("Input your third triangle side");
        double side3 = pikachu.nextDouble();
        if(side1+side2>side3 || side2+side3>side1 || side1+side3>side2)
        {
            double heron=TriangleArea(side1, side2, side3);
            System.out.println("Your triangle area is"+ heron);
        }
        else
        {
            System.out.println("You're Stupid");
        }
    }
    public static double TriangleArea(double side1, double side2, double side3)
    {
        double s= (side1+side2+side3)/2;
        double Heron= Math.sqrt(s*(s-side1)*(s-side2)*(s-side3));
        return Heron;
    }
}
18.import java.util.*;
public class problem18
{
    public static void main(String [] args)
    {
        Scanner pikachu = new Scanner(System.in);
        System.out.println("Input your phrase");
        String phrase = pikachu.nextLine();
        for(int length = 1; length <= phrase.length(); length++)
        {
            System.out.println(phrase.substring(length-1,length));
        }
    }
}
20.import java.util.*;
public class Problem20
{
    public static void main(String[] args)
    {
        Scanner Pikachu = new Scanner(System.in);
        System.out.print("On what day of the month were you born");
        int day = Pikachu.nextInt();
        System.out.print("What is the name of the month in which you were born?");
        String month = Pikachu.next();
        System.out.print("During what year were you born?");
        int year = Pikachu.nextInt();
        System.out.println("You were born on"+ month + day + "," + year + ".You're mighty old");
    }
}
22.import java.util.*;

public class Problem22
{
  public static void main(String [] args)
  {
      Scanner pikachu = new Scanner(System.in);
      System.out.print("What is your GPA?");
      double GPA = pikachu.nextDouble();
      System.out.print("What is your SAT score?");
      int SAT = pikachu.nextInt();
      if(GPA>=1.8 || SAT>= 900)
      {
          System.out.println("You have been accepted");
      }
      else
      {
          System.out.println("You have been rejected");
      }
  }
}