The length of a rectangle is four times its width. The perimeter is 100 cm. What is the number of square centimeters in the area of the rectangle?
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
The length of a rectangle is four times its width. The perimeter is 100 cm. What is the number of square centimeters in the area of the rectangle?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
400
The length of a rectangle is four times its width. The perimeter is 100 cm. What is the number of square centimeters in the area of the rectangle?
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