The mean is all of them added together divided by the number, so multiple the mean by the number of sides, 3, and that's the perimeter. 18 x 3 = 54
Answer: x = 24
Step-by-step explanation:
9x - 18 = 7x + 30
9x - 7x = 30 + 18
2x = 48
x = 48/2 = 24
3 is 13 more than 10, and 3 is 30% of 10, so 30% im pretty sure
