The perimeter of an equilateral triangle is 12 cm and the height is 3.5 cm. What is the area of this equilateral triangle?
一等边三角形周长是12厘米，高是3.5厘米，这个等边三角形的面积是多少平方厘米．
<gadget id="calculator">12 / 3</gadget>
<output>4</output>

<gadget id="calculator">3.5 / 2</gadget>
<output>1.75</output>

<gadget id="calculator">4 * 1.75</gadget>
<output>7</output>

<result>7</result>