Question 1105964
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One side + second side + third, longest side = 39


{{{(1/2)*x}}}    + (x-6)       +  x                  = 39


=============>  0.5x + x - 6 + x = 39


2.5x = 39 + 6 = 45  ====>  x = {{{45/2.5}}} = 18.


<U>Answer</U>.  1st side is 9 ft;  2nd side is 12 ft; 3rd, the longest side, is 18 ft.
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Solved.