In the adjoining figure, Δ ABC is circumscribing a circle. Then, the length of BC is
Since lengths of tangents from same external point are equal.
Therefore,
BZ=BL=4cm
Also
AZ=AM=3cm
This gives
MC= 9 – 3 = 6 cm
Similarly LC = MC = 6cm
So length of BC = BL + LC = 4cm + 6cm = 10cm
Therefore, option d is correct.