Answer:
[tex]width \: of \: the \: rectangle \\ = \frac{area \: of \: rectangle}{length \: of \: rectangle} \\ \\ = \frac{45 {x}^{8} \times {x}^{9} }{5 {x}^{3} \times {x}^{4} } \\ \\ = \frac{45 {x}^{8 + 9} }{5 {x}^{3 + 4} } \\ \\ = \frac{45 {x}^{17} }{5 {x}^{7} } \\ \\ = 9 {x}^{17 - 7} \\ \\ = 9 {x}^{10} \: yards \\ \\ \therefore \: width \: of \: the \: rectangle \\ \: \: \: \: \: \: = 9 {x}^{10} \: yards \\ [/tex]