A triangle has a base of 20 meters and a height of 9 meters. What is the area of this triangle in square meters.
一个三角形，底是20米，高是9米．这个三角形的面积是多少平方米．
<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">20 * (9/2)</gadget>
<output>90</output>

<result>90</result>