Wanda made an error in her calculation when converting the percent to a decimal. The correct conversion of 73% to a decimal should be 0.73, not 7.3.
Then, to find 73% of $400, the calculation should be:
\( 0.73 \times 400 = 292 \)
So the error is that Wanda converted the percent to a decimal incorrectly. The correct choice is:
Wanda converted the percent to a decimal incorrectly. It should be 0.73.