We know that the radius of a circle is half its diameter. With this information, and knowing that the diameters of ⊙ S and ⊙ T are 14 and 9 inches, respectively, we can find TS and TY.
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TS=14/2 & & TY=9/2
⇕ & and & ⇕
TS= 7in & & TY= 4.5in
With this information and using the Segment Addition Postulate, we can find SY.