How much string would you need to go around the bottom of a hat shaped like a cone if the radius is 4 inches? (use 3.14 for pi)

a) 12.56 in
b) 25.12 in
c) 50.24 in
d) 120.32 in

How to do this , and can some one explain

(b) suppose that consolidated power decides to use a level of significance of α = .05, and suppose a random sample of 100 temperature readings is obtained. if the sample mean of the 100 temperature readings is x⎯⎯ = 60.990, test h0 versus ha and determine whether the power plant should be shut down and the cooling system repaired. perform the hypothesis test by using a critical value and a p-value. assume σ = 5. (round your z to 2 decimal places and p-value to 4 decimal places.)

The graph shows how many words per minute two students read. drag to the table the unit rate that matches each graph.