Answer:
its the last one I think.
First, convert "of" to x and put this info into an equation:
Let n represent the unknown number.
14.4 % x n= 10.4
n = 10.4 / 14.4%
n = 72.22222
n = ~72
Hope this helps!
<span>Shortest side = x, Longest Side = 4x-1, third side = 18
Equation is x + (4x-1) + 18 = 42 so 5x-1 = 42-18=24 and 5x=25 so x = 5, longest side = 4(5)-1=19, third side=18
Add all 3 (5+19+18) to get 42</span>