right triangle has three sides whose lengths are 13 cm, 12 cm and 5 cm respectively, what is its area in square centimeters?
一个直角三角形，三条边的长分别为13厘米，12厘米和5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>