uses crt;
var
x1, x2, x3, y1, y2, y3, a, b, c: real;
begin
clrscr;
write(‘ x1 = ’);
readln(x1);
write(‘ y1 = ’);
readln(y1);
write(‘ x2 = ’);
readln(x2);
write(‘ y2 = ’);
readln(y2);
write(‘ x3 = ’);
readln(x3);
write(‘ y3 = ’);
readln(y3);
a := sqrt(sqr(x1 - x2) + sqr(y1 - y2));
b := sqrt(sqr(x2 - x3) + sqr(y2 - y3));
c := sqrt(sqr(x1 - x3) + sqr(y1 - y3));
if (a = b) or (a = c) or (b = c) then
write(‘ равнобедренный ’)
else
write(‘ не равнобедренный ’);
readln;
end.