Answer
Maximum lengths of the other two sides are 5 and 15 in.
Work Step by Step
$12+x+3x \leq 32$
$12+4x \leq 32$
$4x \leq 20$
$x \leq 5$
Maximum value of $x$ is $5$.
$x=5$
$3x=3(5)=15$
Maximum lengths of the other two sides are 5 and 15 in.