Okay to find percentages of things you have to take that original value (1500) and multuply it by the percentage. But when you multiply you put the percentage into a decimal and move it over to the right side two decimal places to the left. For example 10.0% would mean you need to multiply by 0.10 okay?
So for this problem you need to do 1500 *.013 and you get 19.5 computers.
Ok, since the ice rink is a square (which has equal sides) if you multiply 404 times four because a square has 4 sides which is equal to 1616 the perimiter is 1616 sqf