A square has a diagonal of 5 centimeters, what is the area of the square in square centimetres?
一个正方形，它对角线长5厘米，这个正方形的面积是多少平方厘米．
<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">5 * (5/2)</gadget>
<output>25/2 = around 12.5</output>

<result>25/2 = around 12.5</result>