For anyone wondering, take both of the numbers and multiply THEM BOTHby two. Many times, people will make the mistake of multiplying the whole equation by 2. But you can't do that.
Imagine you have a rectangle one side is 8m and the other side is 6m. There would two sides of each length. You have four whole sides. Commonly, people will make the mistake of only thinking that there are two sides. But when you realize that there are 4 sides, You see that you would have to multiply each side by two. Thus, getting the answer of it being four times bigger.