The perimeter of a right triangle is 54cm, and the ratio of their three sides is 3:4:5. What is the area of this right triangle?
一个直角三角形的周长是54cm，它们的三条边的比是3：4：5，这个直角三角形的面积是多少．
<gadget id="calculator">3 + 4 + 5</gadget>
<output>12</output>

<gadget id="calculator">3 / 12</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">54 * (1/4)</gadget>
<output>27/2 = around 13.5</output>

<gadget id="calculator">4 / 12</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">54 * (1/3)</gadget>
<output>18</output>

<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">(27/2) * 9</gadget>
<output>243/2 = around 121.5</output>

<result>243/2 = around 121.5</result>