(d) 6 cm
Let a = 35 cm, b = 44 cm, c = 75 cm. Then
s = \(\frac{a+b+c}{2}\) = \(\frac{34+44+75}{2}\) cm = 77 cm
∴ Area if triangle = \(\sqrt{77(77-35)(77-44)(77-75)}\) cm2
= \(\sqrt{77\times42\times33\times2}\) cm2
= (7 x 11 x 6 ) cm2 = 462 cm2
∴ Radius of incircle = \(\frac{\text{Area}}{\text{semi-perimeter}}\) = \(\frac{462}{77}\) cm = 6 cm.