Solve the following math problem efficiently and clearly:

- For simple problems (2 steps or fewer):
Provide a concise solution with minimal explanation.

- For complex problems (3 steps or more):
Use this step-by-step format:

## Step 1: [Concise description]
[Brief explanation and calculations]

## Step 2: [Concise description]
[Brief explanation and calculations]

...

Regardless of the approach, always conclude with:

Therefore, the final answer is: $oxed{answer}$. I hope it is correct.

Where [answer] is just the final number or expression that solves the problem.

Problem: The base of a triangular piece of paper $ABC$ is $12\text{ cm}$ long. The paper is folded down over the base, with the crease $DE$ parallel to the base of the paper. The area of the triangle that projects below the base is $16\%$ that of the area of the triangle $ABC.$ What is the length of $DE,$ in cm?

[asy]
draw((0,0)--(12,0)--(9.36,3.3)--(1.32,3.3)--cycle,black+linewidth(1));
draw((1.32,3.3)--(4,-3.4)--(9.36,3.3),black+linewidth(1));
draw((1.32,3.3)--(4,10)--(9.36,3.3),black+linewidth(1)+dashed);
draw((0,-5)--(4,-5),black+linewidth(1));
draw((8,-5)--(12,-5),black+linewidth(1));
draw((0,-4.75)--(0,-5.25),black+linewidth(1));
draw((12,-4.75)--(12,-5.25),black+linewidth(1));
label("12 cm",(6,-5));
label("$A$",(0,0),SW);
label("$D$",(1.32,3.3),NW);
label("$C$",(4,10),N);
label("$E$",(9.36,3.3),NE);
label("$B$",(12,0),SE);
[/asy]
user