Answer:
QR = 7.6 cm
Step-by-step explanation:
By theorem of tangents drawn from an external point to a circle,
"Tangents drawn from an external point to a circle are equal in measure"
By this property,
PQ = PT = 3.8 cm
And PR = PT = 3.8 cm
Since, QR = PQ + PR [By segment addition postulate]
QR = 3.8 + 3.8
QR = 7.6 cm