An area is 13,554 square feet. This area increases to 18,341 sq ft. What is percentage of the increase in square footage?

To calculate percentage change subtract the original value from the new value, then divide the result by the original value and convert to a percentage:

% \ Change = \frac {New\ Value\ -\ Original \ Value}{Original \ Value}

For example: if the original value is 1200 and the new value is 1500 the percent change is (1500-1200)/1200 = 1/4 = 25%.

Now apply this technique to your problem - what do you get?

Thank you. My answer is 35%!