If the base of a triangle is 7 decimeters and twice its height, what is its area in square centimeters?
一个三角形的底是7分米，是高的2倍，它的面积是多少平方厘米．
<gadget id="calculator">7 / 2</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">(7/2) / 2</gadget>
<output>7/4 = around 1.75</output>

<gadget id="calculator">7 * (7/4)</gadget>
<output>49/4 = around 12.25</output>

<result>49/4 = around 12.25</result>