Points in circle

circle.pas

program circle;

const
    N = 3;

type
    coords = array [1..N] of real;

var
    x, y : coords;
    x0, y0, r : real;
    d : real;
    i : integer;

begin
    for i := 1 to N do begin
        write('Enter x coordinate for point number ', i, ' >> ');
        readln(x[i]);
    end;

    for i := 1 to N do begin
        write('Enter y coordinate for point number ', i, ' >> ');
        readln(y[i]);
    end;


    write('Enter x coordinate of circle centre >> ');
    readln(x0);
    write('Enter y coordinate of circle centre >> ');
    readln(y0);
    write('Enter the circle radius >> ');
    readln(r);

    writeln;
    for i := 1 to N do begin
        d := sqrt( sqr(x[i]-x0) + sqr(y[i]-y0) );
        if d <= r then
            writeln('Point #',i,' (',x[i]:3:2,',',y[i]:3:2,') is in the circle');
    end;
    readln;
end.