Which algebraic property is used to rewrite (3 + m) + y as 3 + (m + y)?

Find the length of the normal and the angle it makes with the positive x-axis. (see pictured below)

Arectangular yard has area 96 square feet. if the width of the yard is 4 feet less than the length

An amusement park manager determined that about 23 of all customers would wait in long lines to ride the new roller coaster. which simulation could not be used to answer questions about whether a customer would wait?