1/n^2 = 3/192

[math_celebrity]

1/n^2 = 3/192

Cross multiply:
192 * 1 = 3 * n^2
3n^2 = 192

Divide each side by 3:
3n^2/3 = 192/3

Cancel the 3's on the left side:
n^2 = 64

Take the square root of both sides:
n = 8 or -8