Argues that the derivation of the area of a circle using integral calculus is invalid. Describes the derivation of the area of a circle when the formula is not known by inscribing and circumscribing the circle with regular polygons whose areas converge to the same number. (MDH)

Utilizes vector mathematics to explain the reflective properties of a corner cube retroreflector, consisting of three plane mirrors assembled at right angles with a common vertex. Analyzes the useful property that an incident beam of light at any point in this reflector will return on a parallel path. (MDH)