Depreciation by three methods; partial years

Perdue Company purchased equipment on April $1$ for $$73,440.$ The equipment was expected to have a useful life of $3$ years, or $5,940$ operating hours, and a residual value of $$2,160.$ The equipment was used for $1,100$ hours during Year $1,2,100$ hours in Year $2,1,800$ hours in Year $3,$ and $940$ hours in Year $4.$

Required:

Determine the amount of depreciation expense for the years ended December $31,$ Year $1,$ Year $2,$ Year $3,$ and Year $4,$ by $($a$)$ the straight$-$line method, $($b$)$ the units$-$of$-$activity method, and $($c$)$ the double$-$declining$-$balance method.

Note: FOR DECLINING BALANCE ONLY, round the final multiplier to four decimal places. Then, round the answer for each year to the nearest whole dollar.

a$.$ Straight$-$line method

$\backslash$table$[[$Year$,$Amount$],[$Year $1,$$$17,820$