\line
\line(xslope,yslope){length}
The \line
command draws a line with the given length and
slope xslope/yslope.
Standard LaTeX can only draw lines with slope = x/y,
where x and y have integer values from −6
through 6. For lines of any slope, not to mention other shapes,
see the curve2e
and many many other packages on CTAN.