In an ordered pair the x-coordinate represents the number of octagons, and the y-coordinate represents the total number of sides. if the x-coordinate is 9, what is the y-coordinate?

Y would equal 72

Reason- 
     If X represents the total amount of octagons, and Y represents the total sides of all octagons (an octagon has 8 sides). So, if you take the total amount of octagons (9) and counted the sides of ALL of them you'll get 72. Another way is to multiply 9 * 8 = 72

If the x-coordinate is the number of octagons and the y-coordinate is the number of total sides and an octagon has 8 sides and the x-coordinate is 9 then the y-coordinate is 72.