The number of chorus students increase by a factor of 1.2 from the previous year. Write 1.2 as a percent

1.2 as a percent is 120%, so the students in chorus increased by 120%.

Since the percent sign has 2 zeros:% then that means to convert a decimal to a percent, move the decimals to the right 2 spaces. Now, 1.2 should look like this:120. You add the zero because that space is worth nothing, but it is used for the spaces.