A building with a cost of $157,500 has an estimated residual value of $31,500, has an estimated useful life of 9 years, and is depreciated by the straight-line method. a. What is the amount of the annual depreciation? $fill in the blank 1 18,000 b. What is the book value at the end of the fifth year of use? $fill in the blank 2 67,500 c. If at the start of the sixth year