The mathematics that expresses the inversely proportional relationship between wavelength and frequency is simple enough by itself, but there is a novel way to represent the relationship graphically using geometric relationships.

The right triangle provides a particularly useful mode of presentation as it allows the inverse proportional relationship to be expressed using geometric and/or trigonometric relationships.

The basic relationships using SI units are illustrated in the TrianglePair-SI.pdf item.

http://www.vip.ocsnet.net/~ancient/TrianglePair-SI.pdfThe constant of proportionality is the product of the hypotenuse of one triangle and the vertical leg of the other. When the products of both pairs are equal the triangles are mutual, one is the inverse of the other.