What is the length of ST?

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1 Answer

#ST=sqrt210 ~~14.49# inches

Explanation:

By tangent-secant theorem , we have

#"(T angent)"^2="(Whole Secant)"##xx"(External Secant)"#

#i.e. TS^2=TQxxTR#

Tangent #=TS#

Whole Secant #=TQ==TR+RQ=7+23=30 # inches

External Secant #=TR=7# inches

#rarrST^2=RTxxQT#

#toST=sqrt(RTxxQT#

#rarrST=sqrt(7xx30)=sqrt(210)~~14.49# inches