Let a = {1, 2, 3, 4, 5, 6, 7, 8, 9}. n distinct integers will be chosen from a. how big does n have to be
to ensure that the sum of two of the chosen integers is 9?

Angle xyz is formed by segments xy and yz on the coordinate grid below: a coordinate plane is shown. angle xyz has endpoints at 3 comma negative 1 and 6 negative 2 and 3 comma negative 3 and measures 36.87 degrees. angle xyz is rotated 270 degrees counterclockwise about the origin to form angle x′y′z′. which statement shows the measure of angle x′y′z′?