Revision of Depreciation A building with a cost of $641,250 has an estimated residual value of $128,250, has an estimated useful life of 27 years, and is d a. What is the amount of the annual depreciation? b. What is the book value at the end of the fifteenth year of use? and is depreciated by the straight-line method. tf at the start of the sixteenth year it is estimated that the remaining life is 15 years and that the residual value is $26.250, what is the depreciation expense for each of the remaining 15 years?