In triangle ABC, angle C is a right angle. If cos A=5/8, what is the value of cos B? (sqrt(x) = square root of x)
A. 3/8
B. 5/8
C. sqrt(39)/8
D. sqrt(89)/8

In a recent telephone survey, 5,000 randomly selected teenagers were asked to cite their primary social network site. six of 10 teenagers said they use mybook as their primary social network site. a 95% confidence interval to estimate the true proportion of teenagers who use mybook as their primary social network site is found to be (0.2964, 0.9036). which of the following is a correct interpretation of the confidence level? ninety-five percent of all samples of this size would yield a confidence interval of (0.2964, 0.9036). there is a 95% chance that the true proportion of teenagers who use mybook as their primary social network site is in the interval (0.2964, 0.9036). ninety-five percent of the time, the procedure used to generate this interval will capture the true proportion of teenagers who use mybook as their primary social network site. ninety-five percent of all the samples of size 5,000 lie in the confidence interval (0.2964, 0.9036).