Does anybody know the answer to this?

He weights of 2-pound bags of best dog food are approximately normally distributed with a given mean  and standard deviation  according to the empirical rule, what percentage of the bags will have weights within 3 standard deviations of the mean? 47.5%68%95%99.7%

If tan2a=cot(a+60), find the value of a, where 2a is an acute angle

Cd is the perpendicular bisector of both xy and st, and cy=20. find xy.