the square root of 45 is 6.7 so since you need a width four until less than the length you take away 2 from 6.7 to now have 4.7 (width ) and add the other half of four to the length so 6.7 plus 2 is 8.7 (length) and to check it do 4.7 times 8.7 is about 40 it's off because the square root of 45 ihas many places after the decimal and it's be difficult to round them all but the more precise you go the closer to 45 you'll get. Hope that helps
