Can someone explain this? Are my answers for 2 and 4 good?

How do businesses a country's economy? a. by investing in goods and services b. by increasing the unemployment rate c. by making profits

Aman is 6 feet 3 inches tall. the top of his shadow touches a fire hydrant that is 13 feet 6 inches away. what is the angle of elevation from the base of the fire hydrant to the top of the man's head?

Consider the set of all four-digit positive integers less than 2000 whose digits have a sum of 24. what is the median of this set of integers?