At a certain time of day a 6 ft man casts a 4ft shadow, at the same time day how tall is a tree that casts am 18ft shadow?

The teacher didn't explain this at all and i don't understand this

"in english, write six to eight sentences comparing cultural aspects of greetings in spanish-speaking countries with greetings in your own culture. use what you learned in the lessons to tell about three differences and three similarities. discuss non-verbal greetings and how respect is shown. you may also include verbal greetings, but do not simply translate phrases from one language to another."

Choose the answer that best relates to the class or field of study listed below la quimica a. la informatica b. la educacion fisica c. las ciencias sociales d. las ciencias