Volatility is Usually Standard Deviation, Not Variance
In finance, volatility is usually understood as standard deviation.
Of course, variance and standard deviation are very closely related (standard deviation is the square root of variance), but the common interpretation of volatility is standard deviation of returns, and not variance.
Here you can find more details:
Variance vs. Standard Deviation
For more information about the difference between variance and standard deviation and for step-by-step calculation of both, see: