Let X be any point on side AB.
Given that, XM∥ABandXN∥AC
To prove that, TX2=TB.TC
Proof:- BN∥XM
Now,
In ΔTXM,By using Basic proportionality theorem, we have
TBTX=TNTM......(1)
Now,
In ΔTCM, By using Basic proportionality theorem, we have
TXTC=TNTM......(2)
By equation (1) and (2) to, we get
TBTX=TXTC
⇒TB.TC=TX2
⇒TX2=TB.TC
Hence proved.