Eighty percent of a roof, or 2800 square feet of the roof, has been re-shingled. What is the total area of the roof? a. 22,400 sq ft b. 2240 sq ft c. 3500 sq ft d. 35000 sq ft

Given that "80% of the roof" is same as "2800 square feet of the roof".
Let's consider total area of roof = X square feet.
Then "80 percent of X" = "2800 square feet".[tex] 80\% \;of X = 2800 \;square \;feet \\\\\frac{80}{100} *X = 2800 \;square \;feet \\\\\frac{4}{5} *X = 2800 \;square \;feet \\\\X = \frac{5}{4}* 2800 \;square \;feet \\\\X = \frac{14000}{4} \;square \;feet \\\\X = 3500 \;square \;feet \\\\ [/tex]So total area of the roof would be 3500 square feet.Hence, option C is correct i.e. 3500 square feet.