Ptolemy's table of chords to the arc angle in degrees as is to 3, or more precisely, the ratio can be made as close as desired to ≈ by making "θ" small enough. Thus, for the arc of °, the chord length is slightly more than the arc angle in degrees. As the arc increases, the ratio of the chord to the arc decreases. When the arc reaches 60°, the chord length is exactly equal to the number of degrees in the arc, i.e. chord 60° = 60. For arcs of more than 60°, the chord is less than the arc, until an arc
The Three Degrees at The Royal Albert Hall" (aka "An Evening with The Three Degrees"), was recorded in October 1979 in which the trio were backed by the Royal Philharmonic Orchestra. In 1980, the compilation album "Gold" was released and became a UK Top 10 hit. Featuring one side of their hits on the Ariola label between 1978–79, and one side of live recordings from their 1979 Royal Albert Hall television special, this would be the trio's second "best of" compilation to make the UK Top 10 in less than two years, after CBS released "A Collection of their 20 Greatest Hits" in