Use 35 cm wire to form an isosceles triangle, and the length ratio of the two sides is 3:1, what is the length of the waist in cm
用35厘米的铁丝围成一个等腰三角形，其中两条边的长度比是3：1，则腰长多少cm
<gadget id="calculator">3 + 3 + 1</gadget>
<output>7</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">35 * (3/7)</gadget>
<output>15</output>

<result>15</result>