0 a type of mathematics that deals with the relationship between the angles and sides of triangles, used in measuring the height of buildings, mountains, etc. -- (數學中的)三角學
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.
再长的路,一步步也能走完,再短的路,不迈开双脚也无法到达。