Answer:

Step-by-step explanation:

He gains 6 Pounds a month, overall he gains 72 pounds in 12 months
18. 17.9
19. 21.1
20. I cant see the numbers sorry; if the sides are 6, √85 than it should have an angle of 40.6
There are no numbers that are both prime and square.
In addition, only one prime number is even, which is 2.
No 9.717 is greater than 9.707 because 9.717 would be seven hundred seven thousandths and 9.717 would be seven hundred seven teen hundredths.