(b) 72 cm2
Here sm = \(\frac{9+12+15}{2}\) = 18 cm, where lengths of medians are m1 = 9 cm, m2 = 12 cm, m3 = 15 cm.
∴ Area of triangle = \(\frac{4}{3}\sqrt{18(18-9)(18-12)(18-15)}\) cm2
= \(\frac{4}{3}\sqrt{18\times9\times6\times3}\) cm2 = \(\frac{4}{3}\) x 9 x 6 cm2 = 72 cm2.