Answer
$x=6$ cm is the length of the shortest side.
Work Step by Step
The perimeter of a triangle can be calculated as:
$P=a+b+c$, where a, b and c are the lengths of its sides
Here: $a=2x$, $b=2x$, $c=x$, $P=30$ cm, by substituting, we get:
$30=2x+2x+x$
$30=5x$
$x=6$ cm, this is the length of the shortest side.
