In given figure pa is common tangent and qb and pc are tangents from q and p to the smaller and larger circle resp.
If qb=5cm and pc=9cm then evaluate value of pa.

Dear student,

PA and PC are tangents to the circle at the same external point P

Therefore, PA = PC
                  PA = 9cm

​also, if it is asked to find PQ
then, AP= AQ + PQ
​PQ = AP - AQ
​Here AQ = BQ= 5 cm (as AQ and BQ ​ are tangents to the circle at the same external point P)
then ​​PQ = AP - AQ
PQ = 9 - 5 = 4 cm

Regards