If 4 rectangles with a perimeter of 4.5 cm are used to form a square, what is the area of the square in square centimetres?
用4个周长是4.5厘米的长方形拼成一个正方形，这个正方形的面积是多少平方厘米．
<gadget id="calculator">4.5 / 2</gadget>
<output>2.25</output>

<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">2.25 / 5</gadget>
<output>0.45</output>

<gadget id="calculator">2.25 - 0.45</gadget>
<output>1.8</output>

<gadget id="calculator">1.8 * 0.45 * 4</gadget>
<output>3.24</output>

<result>3.24</result>