Enlarge 6 in x 10 in picture to 3 feet x 4 feet.

What is the scale factor and how much of the space will be used?

2 answers

6":3' = 6:36 = 1:6
10":4' = 10:48 = 5:24

so, use the smaller scale factor, and ((24/5)/6)^2 = 16/25 of the space will be used.
6 in expands to 36 in
that would be times 6

10 in expands to 48 in
that would be times 4.8

so the 10 inch dimension is limiting
and the scale ratio is 4.8

6*4.8 = 28.8 inches

so what is used is 28.8 in x 48 in