3 Sand is falling on a conical pile at the rate of 8%. If the height of the pile is always 3 times the radius, find the rate at which the radius is changing when the radius is 5.5 feet. 3,} di'_ 16 0 0': 3311 min b.) dr_ 32 0 0'! 363 min c.) dr _ 3211 0 d! 363 min as: 32 0 at 36311 min