What is the measure of each interior angle of a regular decagon

How is working backward similar to solving an equation?

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%

Write an inequality for this description. - one fourth of the opposite of the difference of five and a number is less than twenty.