The lengths of the three sides of a triangle are 15 meters, 18 meters and 27 meters respectively. If you want to plant trees (all three vertices) on its three sides, and the distance between every two adjacent trees is equal, how many trees are needed at least? Tree.
一个三角形的三条边长分别是15米、18米和27米，要给它的三条边上栽树(三个顶点都栽)，且每相邻两棵树的间距都相等，最少需要多少棵树．
<gadget id="calculator">15 + 18 + 27</gadget>
<output>60</output>

<gadget id="calculator">60 / 3</gadget>
<output>20</output>

<result>20</result>