Вуаля:
program okrujnost;
const PI=22/7;
var d,l:real;
begin
writeln('Vvedite diametr');
readln(d);
l:=PI*d;
writeln('Dlina okrujnosti- ',l:8:3);
end.
program okrujnost;
var a,b:real;
begin
writeln('Vvedite 1-oe chislo'); readln(a);
writeln('Vvedite 2-oe chislo'); readln(b);
if a