A right-angled scalene triangle has a perimeter of 24 cm and the ratio of the lengths of the three sides is 2:3:4. What is the area of the triangle?
一个直角不等边三角形，周长24厘米，三条边的长度比是2：3：4，这个三角形的面积是多少．
<gadget id="calculator">2 + 3 + 4</gadget>
<output>9</output>

<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">3 / 9</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/3) / 2</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">24 * (2/9) * 24 * (1/6)</gadget>
<output>64/3 = around 21.333333</output>

<result>64/3 = around 21.333333</result>