Central angle intersection points and of the legs of the angle with the circle form a diameter, then is a straight angle. (In radians, .) Let be the minor arc of the circle between points and , and let be the radius of the circle. If the central angle is subtended by , then If the central angle is not subtended by the minor arc , then is a reflex angle and If a tangent at and a tangent at intersect at the exterior point , then denoting the center as , the angles (convex) and are supplementary (sum to 180°). A
How Are Things in Glocca Morra? made up by composer Lane, who had devised a dummy lyric beginning with the line, "There's a glen in Glocca Morra". Harburg liked the name but insisted on changing the line to "How are things in Glocca Morra?" because this is personal and immediately evocative of nostalgia and homesickness. James Stephens' work "The Crock of Gold" (first published in 1912) refers to "the leprechauns of Gort na Gloca Mora" ("the field of the big rock" in Gaelic). It is unknown whether Lane or Harburg were aware of the novel or if this is a coincidence. Many versions of this song