1 divided by 7/8? help?

What two criteria are needed for triangles to be similar

Agraphic designer created a logo on eight and a half by 11 inch paper. in order to be placed on a business card, the logo needs to be one and 7/10 inches by 2 and 1/5 in. what is the scale factor of the dilation

Robert is placing sod in two square shaped areas of his backyard. one side of the first area is 7.5 feet. one side of the other area is 5.7 feet. the sod costs y dollars per square foot