勾股玄就解决了。

Draw a triangle, and put the 20 as base. Use the 20 as base, the height is 66=1/2*20*H, therefore, height is 6.6.

 

Then you can use the 13 length side, and the height to figure out the part of the base close to the 13 length side, which is 11.2. The other part is 20-11.2, i.e. 8.8. Finally, you can solve the side X with the height and 8.8. X^2=8.8^2+6.6^2, x=11.

所有跟帖： 

• 谢谢。有知识就是比盲人好！ -周游列国逍遥人生- ♂ (0 bytes) () 12/07/2012 postreply 06:43:35