1

class normal                     {
public static void main (String[] args){
        int a=40,b=45;
        System.out.println("Ploscha pramokutnogo trikutnika "
                + a+" и "+ b+ " равна " +(a*b)/2);
        double c=Math.sqrt(a*a+b*b);
        System.out.println("Perimetr pramokutnogo trikutnika "
                + a+" и "+ b+ " gipotuneza " + (float) c+" rovno " +(float)(a+b+c));
    }
}

2

package com.company;

public class Main {

    public static void main(String... args){
        for(int i = 1; i < 11; i++){
            for(int k = 1; k < 11; k++){
                System.out.print(k * i + " *");
            }
            System.out.println("");
        }
    }}

4

package com.company;

public class Main {
    public static void main(String[] args) {
                System.out.println("Цикл while");
                int i = - 11;
                while (i++ < 25) {
                    System.out.print(i + ", ");
                }
                System.out.println(" ");
                System.out.println("Цикл do while");

                int k = - 10;
                do {
                    System.out.print(k + ", ");} while(k++ < 25);
                System.out.println(" ");

                System.out.println("Цикл For");

                int c = -10;

                for (c = -10; c < 26; c++){
                    System.out.print(c + ", ");
                }
            }
        }
    }
}