With the help of the trapezoid rule, it is possible to perform both smoothing and cutting of the plaster layer, which makes it possible to use materials of various ductility (with cement and gypsum mixtures), and also to repair significant chipping and potholes on the finish surface. In addition, with the help of a trapezoid rule, it is possible to apply the material on a scraper, which allows using this tool to work with thin layers (for precise correction of the geometry of the surface). Due to the straight wide edge, trapezoid rule are widely used as supports for positioning the lower rows of tile and mosaic facings.