Lets use 1 to solve this problem because it is easiest to show.
Multiply 1 by 1.3 for a 30% increase (1*1.3=1.3).
Then multiply 1.3 by .7 for a 30% decrease. (1.3*.7=.91)
Therefore the page had a 9% reduction from its original size or is 91% of its original size.