Equilateral triangle is the only triangle with integer sides and three rational angles as measured in degrees. The equilateral triangle is the only acute triangle that is similar to its orthic triangle (with vertices at the feet of the altitudes) (the heptagonal triangle being the only obtuse one). Equilateral triangles are found in many other geometric constructs. The intersection of circles whose centers are a radius width apart is a pair of equilateral arches, each of which can be inscribed with an equilateral triangle. They form faces of regular and uniform polyhedra. Three of the five Platonic solids are composed of equilateral
Lectures of the Three Degrees in Craft Masonry Lectures of the Three Degrees in Craft Masonry The Lectures of the Three Degrees in Craft Masonry is a series of manuals on Freemasonry that are arranged in the form of catechisms to be memorized. They cover rituals and symbolism associated with the three degrees of Craft Freemasonry in question and answer form. During the second half of the 19th century, the Lectures gradually ceased to be used regularly in English Lodges. The question and answer procedure was the traditional way in which Freemasons were instructed in Masonic ritual and symbolism before printed ritual books became more widely available. Usually,