I need help with Geometry

Acircle has a circumference of 7.850 units. what is its radius?

Benjamin is making bow ties. how many 1/2yards lomg bow ties can he make if he has 18 feet of fabric?

According to a study conducted in 2015, 18% of shoppers said that they prefer to buy generic instead of name-brand products. suppose that in a recent sample of 1500 shoppers, 315 stated that they prefer to buy generic instead of name-brand products. at a 5% significance level, can you conclude that the proportion of all shoppers who currently prefer to buy generic instead of name-brand products is higher than .18? use both the p-value and the critical-value approaches.