uses crt;

var xa, xb, xc, ya, yb, yc : integer;

p, cv, s, a, b, c  : real;

begin

clrscr;

write('nhap toa do diem A : ');readln(xa, ya);

write('nhap toa do diem B : ');readln(xb, yb);

write('nhap toa do diem C : ');readln(xc, yc);

a := sqrt(sqr(xb - xc) + sqr(yb - yc));

b := sqrt(sqr(xa - xc) + sqr(ya - yc));

c := sqrt(sqr(xb - xa) + sqr(yb - ya));

if (a + b > c) and (b + c > a) and (a + c > b) then

begin

writeln('toa do ba diem tao thanh tam giac');

if (a = b) and (b = c) then writeln('tam giac deu') else

if (a = b) or (b = c) or (c = a) then writeln('tam giac can') else

if (a*a = b*b + c*c) or (b*b = a*a + c*c) or (c*c = b*b + a*a)

then writeln('tam giac vuong') else

writeln('tam giac thuong');

cv := a + b + c;

p := cv / 2;

s := sqrt(p * (p - a) * (p - b) * (p -c));

writeln('chu vi : ', cv:2:2);

writeln('dien tich : ', s:2:2);

writeln('toa do trong tam : ', (xa + xb + xc) / 3 :2:1, (ya + yb + yc) / 3 :5:1);

end

else writeln('toa do ba diem khong tao thanh tam giac');

readln

end.