please help i dont understand this math: It costs $3.45 to buy 3/4 lb of chopped walnuts. How much would it cost to purchase 7.5 lbs of walnuts?

Pleasseee important quick note: enter your answer and show all the steps that you use to solve this problem in the space provided. use the circle graph shown below to answer the question. a pie chart labeled favorite sports to watch is divided into three portions. football represents 42 percent, baseball represents 33 percent, and soccer represents 25 percent. if 210 people said football was their favorite sport to watch, how many people were surveyed?