If the two sides of a right triangle are 15 cm and 18 cm respectively, what is its area in square centimeters?
一个直角三角形的两条直角边分别是15厘米和18厘米，它的面积是多少平方厘米．
<gadget id="calculator">15 / 2</gadget>
<output>15/2 = around 7.5</output>

<gadget id="calculator">18 * (15/2)</gadget>
<output>135</output>

<result>135</result>