The three sides of a right triangle are 12cm, 15cm, and 20cm respectively. What is the area of this triangle in square centimeters?
直角三角形三条边分别是12cm、15cm、20cm，这个三角形的面积是多少平方厘米？
<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<gadget id="calculator">15 * 6</gadget>
<output>90</output>

<result>90</result>