Answer
$25.6$ ft
Work Step by Step
The base of the figure is $55.6$ ft long.
This length is equal to the sum of the three horizontal line segments on top of the figure. Two of those three horizontal line segments are both $15$ ft long, so their total length is $30$ ft.
Thus, the length of the third horizontal line segment, which is labeled $A$, is the difference between $55.6$ ft and $30$ ft.
Subtract the numbers (write $30$ as $30.0$) to obtain:
\begin{array}{ccc}
&&55.6
\\&- &\underline{30.0}
\\&&25.6
\end{array}
