Answer:
fourth number is 9
Step-by-step explanation:
let 'x' equal the fourth number
(5+7+7+x)/4 = 7
cross-multiply to get:
19 + x = 28
x = 9
Answer:
9 is the fourth number.
Step-by-step explanation:
9 is the fourth number because 7(mean) x 4(amount of numbers) = 28 and 7 plus 7 plus 5 plus 9 equals 28 so when you divide you get 7.