Answer:
4 5 9
11 6 1
3 7 8
Step-by-step explanation:
In a magic square, all rows, columns, and diagonals have the same sum.
Let's call the cells a - i this way:
a b c
d e f
g h i
Now lets's fill in what we have:
a b 9
11 6 1
g h i
2nd row: 11 + 6 + 1 = 18
3rd column: 9 + 1 + i = 18; i = 8
a b 9
11 6 1
g h 8
Main diagonal: a + 6 + 8 = 18; a = 4
4 b 9
11 6 1
g h 8
1st row: 4 + b + 9 = 18; b = 5
4 5 9
11 6 1
g h 8
1st column: 4 + 11 + g = 18; g = 3
4 5 9
11 6 1
3 h 8
2nd column: 5 + 6 + h = 18; h = 7
4 5 9
11 6 1
3 7 8