若2△3=2+3+4=9，5△4=5+6+7+8=26．按此规律，5△5=______．
5△5=5+6+7+8+9=35；
故答案为：35．
A figure eight knot is used to（）.
A.be a stopper
B.shorten a line
C.join lines of equal size
D.keep a line from passing through a sheave
