By the law of cosines, the angle

satisfies

which reduces to

which converts to approximately 77 degrees (this can be done my multiplying by 180 and dividing by pi).
Answer:
324
Step-by-step explanation:
given that in a poll, 74% of the people polled answered yes to the question "Are you in favor of the death penalty for a person convicted of murder?"
i.e. Sample proportion 
Margin of error = 4% = 0.04
Confidence level =90%
Z critical value for 90% = 1.645
Margin of error = 1.645 * std error
Hence std error = 
Std error is also equal to

Sample size should be 324.
The formula is sample size = (Z critical value)^2 (pq)/(Margin of error )^2
120 barrels x 12 quarts per barrel = 1440 total quarts
1440 quarts / 11 quarts per hour = 130.91 hours to fill all the barrels
1 day = 24 hours
130.91 hours / 24 hours = 5.45 days = 5.5 days