Help DS一题

yalemba

一题 DS:

A man 6 feettall is standing near a pole. On the top of the pole is light. What is the length of the sadow cast by the man?

(1) the pole is 18 feet high

(2) the man is 12 feet from the pole

A: C

麻煩 说明一下? why 

yalemba

恩恩 thankyou !!

下午 画了圆 看不出來　

经lz提醒后　又画了一次～ 我真是猪头