A piece of iron wire with a length of 13 cm is made into an isosceles triangle with a waist length of 5 cm. What is the length of its base in cm?
把一根长13厘米的铁丝做成一个腰长是5厘米的等腰三角形，它的底边长是多少厘米．
<gadget id="calculator">13 - 5 - 5</gadget>
<output>3</output>

<result>3</result>