Which line is perpendicular to a line that had a slope of -5/6

Asimple random sample of size nequals14 is drawn from a population that is normally distributed. the sample mean is found to be x overbar equals 70 and the sample standard deviation is found to be sequals13. construct a 90% confidence interval about the population mean

Find the value of tan theta if sin theta = 12/13 and theta is in quadrant 2

What is this inequality notation? t is less then or equal to 2