First we write 7 out of 9 as the fraction 7 / 9.
To get a decimal representation, we divide 7 by 9 and get .777…
We multiply by 100 or move the decimal place two places to the right to get 77.8% (note that we rounded to the nearest tenth of a percent).
It is important to note that:
7 / 9 = .777…= 77.8%