If the lengths of the two sides of a triangle are 5 cm and 4 cm respectively, then the third side must be less than how many centimeters.
一个三角形两条边的长分别是5厘米和4厘米，那么第三条边一定小于多少厘米．
<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<result>9</result>