Thread: half chords

Hello everyone,

Could someone please help me on this problem?

The half chords of twice the angle woudl make sense for the 60 degree angle and also for the 30 and 45 degree angle[twice 90 and twice 120 do not make sense-why?] Figure out what the half chords are and whether they are the same as our modern sines of the angles.

My attempt:

sin30=1/2
sin45=square root of 2/2
sin 60=square root of 3/2

Thank you very much

Does anyone know what a half-chord is? It is just half of a chord?

Thank you