Q.In triangle ABC, a straight line parallel to side BC intersects AB at point P and AC at point Q. If AP = 4 cm, QC = 9 cm, and PB = AQ, then find the length of PB.
AP = 4 cm, QC = 9 cm, and PB = AQ
In this case, \(\cfrac{AP}{PB} = \cfrac{AQ}{QC}\)
So, \(\cfrac{4}{PB} = \cfrac{PB}{9}\)
Therefore, \(PB^2 = 36\)
So, \(PB = 6\)
\(\therefore\) The length of PB is 6 cm.