Use 72 cm long wire to form a triangle. The ratio of the lengths of the three sides of the triangle is 3:4:5. What is the length of the longest side in centimeters?
用72厘米长的铁丝围成一个三角形，三角形三条边长的比是3：4：5，最长的一条边长是多少厘米？
<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">72 * (5/12)</gadget>
<output>30</output>

<result>30</result>