There is a square flower bed in the square with a side length of 16 meters. If the flower bed is surrounded by a guardrail of 9 yuan per meter, how much will it cost?
广场上有一个正方形花坛，边长16米，如果用每米9元的护栏把花坛围上，需要多少钱？
<gadget id="calculator">16 * 4 * 9</gadget>
<output>576</output>

<result>576</result>