Program dientichtamgiac ;

     Uses crt;

     Var a,b,c,p,S: real;

     Begin

     clrscr;

     Write('Nhap canh a:');readln(a);

     Write('Nhap canh b:');readln(b);

     Write('Nhap canh c:');readln(c);

     p:=(a+b+c)/2;

     S:= sqrt(p*(p-a)*(p-b)*(p-c));

     Write('Dien tich hinh tam giac la',s:3:6);

     Write('chu vi cua hinh tam giac          la',a+b+c);

     Readln

     End.
2. Diện tích chu vi hình chữ nhậtUses crt;
Program dientichhchuvihinhchunhat;

Var s, p, a, b: real;

Begin

     Clrscr;

     Write('Nhap chieu dai HCN: '); readln(a);

     Write('Nhap chieu rong HCN: '); readln(b);

     s:=a*b;

     p:=(a+b)*2;

     Writeln('Dien tich HCN la: ',s1:2:0);

     Writeln('Chu vi HCN la: ',p1:2:0);

Readln

End.
3.diện tích chu vi hình tròn
program chuvidientichhinhtron
Uses crt;

Var r,s1,c1: real;

Begin

Write('Nhap r = ');

readln(r);

c1:=pi*r*2;

s1:=pi*r*r;

Writeln('Dien tich cua hinh tron la: ',s1);

Writeln('Chu vi cua hinh tron la: ',c1);

Readln

End.