Two sides of a triangle are equal in length and double the length of the shortest side. the perimeter of the triangle is 36 inches

The shortest side would be "x" and the two equal sides would be represented with "2x"

With the perimeter being 36, you would insert the sides in this equation-

36/5x   so, your "x" value would be 7.2

The shortest side would be 7.2, and the equal sides would both equal 14.4

I hope this was what you were asking!