PR =12 and PQ =8. Therefore QR=12-8=4
And ST=18
Let SQ=x,then TQ=18-x
Here we have to use the chord intersection formula, which is
PQ*QR = SQ*TQ
8*4 = x(18-x)
Distributing x on 18-x
[tex] 32 = 18x - x^2 [/tex]
[tex] x^2 -18x+32=0 [/tex]
(x-16)(x-2)=0
x-16=0 , x-2=0
x=16,x=2
So SQ =16 and TQ=18-16=2
Therefore the answer is 2 .
