If the perimeter of an equilateral triangle is 18 cm and the height is 5.2 cm, what is its area in square centimeters?
一个等边三角形的周长是18厘米，高是5.2厘米，它的面积是多少平方厘米．
<gadget id="calculator">18 / 3</gadget>
<output>6</output>

<gadget id="calculator">5.2 / 2</gadget>
<output>2.6</output>

<gadget id="calculator">6 * 2.6</gadget>
<output>15.6</output>

<result>15.6</result>