If the two diagonals of a rhombus are 10 cm and 8 cm respectively, what is its area in square centimeters?
菱形的两条对角线分别是10厘米和8厘米，它的面积是多少平方厘米．
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">10 * 4</gadget>
<output>40</output>

<result>40</result>