A rectangle has a length of 24 cm and a width of 9 cm. Cut the largest square out of this rectangle. What is the area of this square?
一个长方形的长是24厘米，宽是9厘米．在这个长方形里剪出一个最大的正方形，这个正方形的面积是多少？
<gadget id="calculator">9 * 9</gadget>
<output>81</output>

<result>81</result>