From the given figure, x should be twice the missing side of the triangle formed.
We get,
[tex]\text{ x = 2}\sqrt[]{2.1^2-1.4^2}[/tex][tex]\text{ x = 2}\sqrt[]{4.41-1.96^{}}[/tex][tex]\text{ = 2}\sqrt[]{2.45^{}}[/tex][tex]\text{ = }3.130495168499706\text{ }\approx\text{ 3.1}[/tex][tex]\text{ x = 3.1 ft.}[/tex]
Therefore, x = 3.1 ft.
