Elemantary school so area=legnth times width to get greatest area, make legnth as close to width as possible in measure
to get least area, make legnth as far away from width as possible in measure perimiter=2 times legnth+2 times width=2 times (legnth+width) 18=2 times (legnth+width) divide 2 9=legnth+width find closest and farthest 1+9 is farthest 4+5 is closest
areas=legnth times with 1 times 9=9 4 times 5=20 differnce is subtract 20-9=11
answe is 11 (note I didn't use decimals since the user is supposedly in elemenatry school)
First, find out how wide his shelf is in inches. 2.25*12=27. So his shelf is 27 inches wide. Then divide that by 2.25 to find the number of encyclopedias will fit.
