MCQ - 109-11961

Correct Answer: A

Explanation:

Let s be the original sidelength of the square. Increasing this by 12% is the same as adding 0.12 times that sidelength to the original sidelength. The new sidelength is, therefore,

s + 0.12s = 1.12s

The perimeter of a square is four times its sidelength. Its original perimeter was 4s; after the increase, it is 4⋅1.12s=4.48s. The percent of the increase is therefore

${\displaystyle \frac{4.48s-<!--\; -\; -->4s}{4s}\times <!--\; \times \; -->100\mathrm{\%<!--\; \%\; -->}=\frac{0.48s}{4s}\times <!--\; \times \; -->100\mathrm{\%<!--\; \%\; -->}=0.12\times <!--\; \times \; -->100\mathrm{\%<!--\; \%\; -->}=12\mathrm{\%<!--\; \%\; -->}}$