Students use pre- and post-1983  pennines to study scatter plots, linear regressions, and equations of lines.  Using area and mass data from wooden and oaktag squares, the students learn to estimate the surface area by (i) using a centimeter grid; and (ii) using equations of lines to compare with the direct counting method.  Students then design their own initial plates that give them an opportunity to express their creativity/individuality and also their newfound skill at being able to estimate surface area by utilizing known mass data.