Answer: Choice A) 8 units
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Step-by-step explanation:
Use the intersecting chords theorem to get
y*6 = 4*12
6y = 48
6y/6 = 48/6
y = 8
Therefore y is 8 units long.
Check:
y*6 = 4*12
8*6 = 4*12
48 = 48
our answer checks out