Draw the largest right-angled triangle in a semicircle. It is known that the perimeter of the triangle is 24cm and the ratio of the three sides is 3:4:5. How much is the area of the semicircle greater than the area of the triangle?
在一个半圆内画一个最大的直角三角形，已知三角形的周长是24cm，三条边之比为3：4：5，求半圆的面积比三角形面积多多少？
<gadget id="calculator">3 + 4 + 5</gadget>
<output>12</output>

<gadget id="calculator">5 / 12</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">(5/12) / 2</gadget>
<output>5/24 = around 0.208333</output>

<gadget id="calculator">24 * (5/24)</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">25 / 2</gadget>
<output>25/2 = around 12.5</output>

<gadget id="calculator">3.14 * (25/2)</gadget>
<output>39.25</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">24 * (5/12) * (5/2)</gadget>
<output>25</output>

<gadget id="calculator">39.25 - 25</gadget>
<output>14.25</output>

<result>14.25</result>