(d) \(\frac{176}{3}\pi\) sq. cm
Given : AB = AC = 10 m, BC = 6 m and ∠A = 30º. The area that the cow can graze is the area of the circle with centre A and radius 8 m. But the cow is not allowed to enter the sector ADE formed inside DABC with ∠A = 30° and AD = AE = 8 cm.
∴ Area grazed = Area of circle – Area of sector ADE
= πr2 - πr2 . \(\frac{30°}{360°}\) = πr2 \(\bigg(1-\frac{30°}{360°}\bigg)\)
= π x 64 x \(\frac{11}{12}\) = \(\frac{176}{3}\pi\) sq. cm