I tried to do my best to solve and show work. If you need an explanation just leave a comment :)
Answer:

Step-by-step explanation:
What times what = 36 like two of the same numbers. then multiply that number by 4 for the number of sides and u get the perimiter. (sry if confusing so ill explain that 6×6=36)
I believe the answer would be d because 7+11 is not greater than 18
Answer:
Rational
Step-by-step explanation:
Because the decimal is repeating like 3.33333333 repeating it would be rational because it can be predicted that the number after it would be 3. If the answer was .5647395043794 with more number after it then it wouldn't be able to be determined and would be irrational.