Area and Perimeter of Dilated Figures

In addition to resolution, pictures also have a PPI (Pixels per inch) value. This helps computers determine how big a picture would be if it was printed. Many photographers, editors and graphic designers use PPI to help print photos for all kinds of people including businessmen, activists, newlyweds, artists and more.$\\$ A photo from iPhone 7 Plus has a resolution of $\text{1080 x 1920}$ and a PPI of 250. If you wanted to use it as a $\text{27" x 48"}$ poster, what percentage should you scale the photo?