Parallelogram Perimeter: Finding the Total Length When One Side is 0.5X

To solve the problem, follow these steps:

• Step 1: Identify the given side lengths.
  The longer side of the parallelogram is given as $0.5X$. The other side, being half the length of the long side, is $0.25X$.
• Step 2: Use the perimeter formula.
  The formula for the perimeter $P$ of a parallelogram is $P = 2a + 2b$, where $a$ and $b$ are the lengths of the sides.
• Step 3: Plug in the side lengths into the formula.
  Substitute $a = 0.5X$ and $b = 0.25X$ into the perimeter formula:
  $P = 2(0.5X) + 2(0.25X) = X + 0.5X = 1.5X$.

Thus, the perimeter of the parallelogram expressed in terms of $X$ is $1.5X$.

Therefore, the correct answer is choice $2$, which is $1.5X$.