Geometric mean

The average that fits ratios and compounding — ⁿ√(x₁·x₂·…·xₙ).

The geometric mean is the right average for ratios, growth rates and compounding.

Formula

GM = ⁿ√(x₁ · x₂ · … · xₙ)

Try it

GM of 4 and 9

√(4·9) = √36 = 6.