If the perimeter of an equilateral triangle is 15 cm and the height is 2.4 cm, what is its area in square centimeters?
一个等边三角形的周长是15厘米，高是2.4厘米，它的面积是多少平方厘米．
<gadget id="calculator">15 / 3</gadget>
<output>5</output>

<gadget id="calculator">2.4 / 2</gadget>
<output>1.2</output>

<gadget id="calculator">5 * 1.2</gadget>
<output>6</output>

<result>6</result>