Straight-Line Depreciation A refrigerator used by a wholesale warehouse has a cost of $64,000, an estimated residual value of $5,200, and an estimated useful life of 12 years. What is the amount of the annual depreciation computed by the straight-line method? Depreciation by Units-of-activity Method A diesel-powered tractor with a cost of $204,760 and estimated residual value of $5,100 is expected to have a useful operating life of 67,000 hours. During February, the tractor was operated 200 hours. Determine the depreciation for the month. If required, carry out any division to two decimal places