Program Tam_giac;
Uses crt;
Var a,b,c,p,s : real;
Begin
Writeln('Nhap do dai canh a: '); readln(a);
Write('Nhap do dai canh b: '); readln(b);
Write('Nhap do dai canh c: '); readln(c);
If (a+b>c) and (a+c>b) and (b+c>a) then
Begin
Write('Do la do dai ba canh cua tam giac');
p:=(a+b+c)/2;
s:=sqrt(p*(p-a)*(p-b)*(p-c));
Write('Chu vi tam giac la: ',2*p);
Write('Dien tich tam giac la: ',s);
End;
If (a+b<c) or (a+c<b) or (b+c<a) then
Write('Do khong phai la do dai ba canh cua tam giac');
Readln
End.