The lengths of the three sides of a right triangle are 5cm, 3cm, and 4cm respectively, what is its area in square centimetres?
一个直角三角形的三条边长分别是5cm、3cm、4cm，它的面积是多少平方厘米．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<result>6</result>