Use 3 identical squares to form a rectangle. The perimeter of the rectangle is 40 cm. What is the area of one of the squares in square centimeters?
用3个完全一样的正方形，拼成一个长方形，长方形的周长是40厘米，其中一个正方形的面积是多少平方厘米．
<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">1 * 2</gadget>
<output>2</output>

<gadget id="calculator">6 + 2</gadget>
<output>8</output>

<gadget id="calculator">40 / 8</gadget>
<output>5</output>

<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<result>25</result>