The width = X, the length = 2x
Area = Length × Breadth
[tex]162 = 2x \times x \\ 162 = 2x {}^{2} [/tex]
dividing both side by 2
[tex] \frac{162}{2} = \frac{2 {x}^{2} }{2} \\ 81 = x {}^{2} [/tex]
squaring both side
[tex] \sqrt{81} = x [/tex]
[tex]x = 9[/tex]