To represent the statement "Twenty percent of your grade is 80 points," we can translate this into an algebraic equation.
Let \( x \) be your grade. According to the statement, twenty percent of \( x \) is equal to 80 points. In mathematical terms, this can be expressed as:
\[ 0.20x = 80 \]
So, the correct option from your list is:
.20x = 80