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: In the diagram, rectangle $PQRS$ is divided into three identical squares. If $PQRS$ has perimeter 120 cm, what is its area, in square centimeters? [asy]

size(4cm);

pair p = (0, 1); pair q = (3, 1); pair r = (3, 0); pair s = (0, 0);

draw(p--q--r--s--cycle);

draw(shift(1) * (p--s)); draw(shift(2) * (p--s));

label("$P$", p, NW); label("$Q$", q, NE); label("$R$", r, SE); label("$S$", s, SW);

[/asy]
user