In Fig. 10.87, two equal circles touch each other at T, if QP = 4.5 cm, then QR =
Given:
QP = 4.5 cm
Property: If two tangents are drawn to a circle from one external point, then their tangent segments (lines joining the external point and the points of tangency on circle) are equal.
By the above property,
PQ = PT = PR = 4.5 cm (tangent from P)
Now,
QR = PQ + PR
QR = PQ + PQ [∵PQ = PR]
QR = 2PQ
QR = 2 × 4.5 cm
QR = 9 cm
Hence, QR = 9 cm