uses crt;

const fi='bai1.inp';

var f1:text;

a,b,c,cv,dt,p:real;

begin

clrscr;

assign(f1,fi); rewrite(f1);

write('Nhap a='); readln(a);</p><p>write('Nhap b='); readln(b);</p><p>write('Nhap c='); readln(c);</p><p>if (a>0) and (b>0) and (c>0) and (a+b>c) and (a+c>b) and (b+c>a) then </p><p>begin</p><p>cv:=a+b+c;</p><p>p:=cv/2;</p><p>dt:=sqrt(p*(p-a)*(p-b)*(p-c));</p><p>writeln(f1,'Chu vi la: ',cv:4:2);

writeln(f1,'Dien tich la: ',dt:4:2);

end

else writeln(f1,'Day khong la ba canh trong mot tam giac');

close(f1);

readln;

end.