Can someone teach me how to do this. i know the answers i just don’t understand how to do it

Find the value of the variable and the length of each secant segment.

If the sales price of a dvd is $20 and the markup is 34%, what is the cost of the dvd?

Max recorded the heights of 500 male humans. he found that the heights were normally distributed around a mean of 177 centimeters. which statements about max’s data must be true? a) the median of max’s data is 250 b) more than half of the data points max recorded were 177 centimeters. c) a data point chosen at random is as likely to be above the mean as it is to be below the mean. d) every height within three standard deviations of the mean is equally likely to be chosen if a data point is selected at random.