3, 6, 12
I guessed and checked. So if 3 is the smallest number, I would, multiply it by 3, which is 9. 9 is 3 less than the largest number which would be 12. 12 + 3 is 15. To find the third number, subtract 21 and 15 which is 6
Answer:
twelve faces
Step-by-step explanation:
12 sides