# Chord geometry

27 questions all stuffed in to the same circle gives students a real challenge. This puzzle is great for any high school geometry lesson on circles. It contains angles with their vertex in the circle, on the circle, and outside of the circle. These angles are all made using diameters, chords, secants and tangents.

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Ptolemy of Alexandria compiled a more extensive table of chords in his book on astronomy, giving the value of the chord for angles ranging from 1/2 degree to 180 degrees by increments of half a degree. The circle was of diameter 120, and the chord lengths are accurate to two base-60 digits after the integer part

Relationship between sound and color. If you could actually "hear" the extremely high frequencies the red, yellow and blue (primary color) light waves are vibrating at... you would hear a Major chord. If you could "see" the sound of notes in a major chord relative to the same "rainbow scale" used by light, you would see notes and chords in primary color

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