In the figure, a common tangent RT is drawn to the circles P and Q. Now in RPT and SQT we have, P=Q=90 T is the common angle i.e. PTR=QTS PRT=QST (third angle) RPTSQT (AAA similarity criteria) RP/SQ=PT/QT=RT/ST Given RT=48, ST=24, QS=7 RP/SQ=PT/QT=48/24 RP/SQ=PT/QT=2 Now, RP/SQ=2 RP=2SQ RP=14(SQ=7) Now, to find QT and PT, let us use Pythagoras theorem on the right angled triangle SQT ST 2 =SQ 2 +QT 2 24 2 =7 2 +QT 2 QT 2 =57649 QT=22.96 Also, PT/QT=2 PT=2QT PT=45.91 PR=14,QT=22.96,PT=45.91