Abstract: The present invention is a sliding ruler square that provides an adjustable and extendible straightedge element permitting a user to conveniently scribe lengthy cut lines at pre-selected angles across a work piece typically utilized in the construction industry without the necessity as exhibited by the prior art to reposition the tool. The inventions comprises a right triangularly shaped base with a fence on one base edge, a sliding straightedge on the other base edge and markings along the straightedge and the hypotenuse and other edges of the base to present a variety of ways to measure and mark. The tool combines a number of measurement and scribing functions typically requiring several tools.