The three sides of a right triangle are 5 cm, 12 cm, and 13 cm. What is its area in square centimetres.
一个直角三角形的三条边分别是5厘米、12厘米、13厘米．它的面积是多少平方厘米．
<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<gadget id="calculator">5 * 6</gadget>
<output>30</output>

<result>30</result>