uses crt;

var a,b,c:integer;

   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));

if (a+b>c) and (b+c>a) and (a+c>b) then write(' Do la ba canh cua tam giac');

writeln('Dien tich cua tam giac la:',s:10:2)

else writeln('Do ko phai la ba canh cua tam giac');

readln;

end.

Uses crt;
var a,b,c:longint; p:real;
begin
clrscr;
   write('a,b,c=');readln(a,b,c);
   if (a+b>c)and(a+c>b)and(b+c>a) then
      begin
         writeln('Day la 1 tam giac.');
         p:=(a+b+c)/2;
         Writeln('Dien tich: ',sqrt(p*(p-a)*(p-b)*(p-c)):0:3);
      end else write('Day khong phai la 1 tam giac.');
readln
end.

//////////////////////////////////////

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