*Diện tích tam giác:
uses crt;
var a,b,c,p:extended;
{---Ham-dien-tich---}
function s(a,b,c,p:extended):real;
begin
if ((a+b)>c) and ((b+c)>a) and ((a+c)>b) then
begin
p:=(a+b+c)/2;
s:=sqrt(p*(p-a)*(p-b)*(p-c));
end;
end;
{---Chuong-trinh-chinh---}
BEGIN
clrscr;
p:=0;
write('Nhap a,b,c: '); readln(a,b,c);
write('Dien tich: ',s(a,b,c,p):0:2);
readln;
END.
*Diện tích hình chữ nhật:
uses crt;
var a,b:extended;
{---Ham-dien-tich---}
function s(a,b:extended):real;
begin
s:=a*b;
end;
{---Chuong-trinh-chinh---}
BEGIN
clrscr;
write('Nhap do dai chieu dai: '); readln(a);
write('Nhap do dai chieu rong (b<a): '); readln(b);
write('Dien tich hinh chu nhat: ',s(a,b):0:2);
readln;
END.
