If the base of a triangle is 3 cm and the height is 2.8 decimeters, what is the area in square centimeters?
一个三角形的底是3厘米，高是2.8分米，面积是多少平方厘米．
<gadget id="calculator">2.8 / 2</gadget>
<output>1.4</output>

<gadget id="calculator">3 * 1.4</gadget>
<output>4.2</output>

<result>4.2</result>