How can i get the arc of a circle with the center angle being 60 and the circumferance is 6?

Which equation represents the partial sum of the geometric series?

The first-serve percentage of a tennis player in a match is normally distributed with a standard deviation of 4.3%. if a sample of 15 random matches of the player is taken, the mean first-serve percentage is found to be 26.4%. what is the margin of error of the sample mean? a. 0.086% b. 0.533% c. 1.11% d. 2.22%

What are the solutions of the equation? 16x^2 + 24x + 5 = 5 a. 1/4, 5/4 b. -1/4, -5/4 c. -1/4, 5/4 d. 1/4 , -5/4