The inquiry-based approach to learning has gained popularity in recent times. Those who promote this approach maintain that mathematical investigation should be used to engage students. The National Council of Teachers of Mathematics (NCTM) recommends that problem solving be the center of mathematics teaching in promoting student learning through problem-solving contexts and inquiry-based environment. Inquiry means involvement that leads to understanding and exposes students to mathematical investigation. Investigation exposes students to different forms of representation. This article reports on one of the three related investigations which were presented to a class of secondary school preservice teachers--the relationship between the length of the view tube (x) and the viewable vertical distance on the wall (y) while keeping the perpendicular distance from the eye to the wall and the diameter of the view tube constant. (Contains 7 figures and 1 table.)