STEP 1

STEP 2

STEP 3

STEP 4

STEP 5

Let PQ and PR touch the circle at points S and U respectively. Join O with P, Q, R, S and U

We have OS = OT = OU = 6cm
QT = 12 cm and TR = 9cm
QR= QT +TR = 12cm + 9cm = 21 cm
Now QT = QS=12 cm (tangent from the same point)

TR =RU=9cm
Let PS =PU =x cm
Then PQ=PS+SQ- (12 + x)cm and PR = PU+RU= (9+x)cm